Read Ch 4 in your Costanzo & Krauss textbook.
Summarize the chapter. What is the most interesting thing you learned? What surprised you the most? What is something you want to learn more about? Search on that topic and report on some additional information about that topic. Provide any links to resources.
Trace evidence is still incredibly unreliable. Fingerprints and DNA, seen as the two most reliable forms of evidence in a criminal case, have major flaws that can often lead to a wrongful conviction or a perpetrator walking away clean. Fingerprint evidence can be flawed due to pressure, surface, or partial prints, not to mention the personal biases of the expert comparing latent prints to the suspect's. On top of everything, juries don't always know enough about probability statements and often misinterpret them.
I found this chapter rather interesting. I had no idea the degree to which trace evidence can be contaminated, misinterpreted, or subject to bias. A couple of things that stuck out at me were that juries are more likely to see two fingerprints as matching after being shown disturbing and gruesome crime scene photos, and that DNA evidence was allowed until about 30 years after its discovery.
The one thing that hit me as inherently flawed was the fact that an overwhelming majority of forensic scientists only have their Bachelor's degrees. Two sites (http://legalcareers.about.com/od/lawenforcementcareers/a/forensicscientist.htm and http://education-portal.com/forensic_scientist.html) state that a Bachelor's degree is only the minimum requirement to become a forensic scientist. Why don't most labs/police forces look for people with more credentials? As the book put it (in so many words), people lacking graduate training in a field are subject to stimuli such as impressing a superior instead of finding the truth.
Chapter four:
Trace evidence can be important to a trial. How it's measured, what characteristics it has, how it's presented and it's reliability and validity all influence its importance in cases. Forensic indetifcation can be objective, such as DNA which involoves measurements, or subjective, where analysis involoves interpretation. Fingerprints are one way to forensically identify a suspect but many complications exist; a probability of error, print quality, variability between analyizers. Psychology gets involoved due to cognitive biases that may effect the subjective nature of evidence, examination striations, tools, teeth, handwriting, hair all have weak vailidity as determining evidence. Biases can affect evidence analysis; supervisors, finances, clients, personal biases, nature of the case. Science is somewhat lacking from this topic. And when it is presented may not be accurately understood by those using the scientific evidence to make judgements in cases.
I found it interesting that examiners are not isolated from the cases in which they are examining eveidence for and that confirmation biases may arise due to this.
I was surprised that there is no more routine retesting of trace evidence. Also, I liked that I was surprised by the fact that the FBI tests for proficiency two times a year. I enjoy the idea of double blind tests so thte examiner doesn't know they are actually being tested. It is crazy to me that 96% of the people working on examining evidence hold only a bachelor degree.
I was interested in learning more about the job field of Forensic Psychology and the expectations that exist for those in the field. The Website below provides a lot of information and the second link, from the same website provides guidelines to those in the profession.
http://www.ap-ls.org/aboutpsychlaw/aboutPsychLaw.php
http://www.ap-ls.org/aboutpsychlaw/080110sgfpdraft.pdf
The most interesting item I learned from in this chapter is how ineffective trace evidence really is unless it is DNA or fingerprint evidence. I knew beforehand that it wasn't as easy to obtain trace evidence and find the perpetrator in real life as it is depicted in shows like CSI. The little passage on if their is a CSI effect is something I also found interesting because I find it true. Most people do think that it is easy to collect and examine evidence, at least they think it's easier than it really is because of shows similar to CSI.
I would like to learn more about the CSI effect on not only jurors but on the public in general. I looked up some articles on the "CSI effect" and I found a pretty good one called "The 'CSI Effect': Does It Really Exist" by Donald Shelton for the National Institute of Justice. He has observed that since the early 2000's when CSI became really popular, more and more juries acquitted more people merely based on the lack of DNA or forensic evidence. This is because they believe that DNA or forensic evidence is the best type of evidence because of their viewing of shows like CSI.
Here's the article: http://www.nij.gov/journals/259/csi-effect.htm
This Chapter is about the evidence left at the scene. There are different kinds of evidence and different uses for the evidence. Evidence whether it be writing, blood, footprints, etc. can be contaminated and is still relatively unreliable. There can be a lot of evidence collected and none used. DNA and fingerprints are still reliable because it is hard to overcome fingerprints that do not match or DNA that does not match the victim/defendant. However, fingerprints can still be inaccurate and misleading. Bias also plays a part. We want to believe that evidence comes from a defendant and evidence shown seems to push us to believe that it did.
It surprised me the fingerprints could be messed up. Maybe it was me watching to much CSI where everything is perfect. I thought that it was more accurate and solid than this chapter had it out to be.
Fingerprints are still used in trial even though they are not as relaible as DNA. Police use the prints found at the scene to identify a suspect. There is also a misconception on how they identify the suspect. Television portrays is as a few minutes in the computer and its done. In real life there is an expert that needs to verify the prints. The problem with this is that different experts have different standards to say the a finger print is a match.
http://www.nolo.com/legal-encyclopedia/fingerprint-evidence-what-you-need-29818.html
Forensic identification holds many errors, but our expanding and growing technology may help minimize the error, maybe even eliminate it. Even the most solid sounding evidence, such as fingerprints, can still be subject to error. Even if technological fixes are eventually found there will still be fundamental problems with fingerprint matching. There will still be weak scientific foundation for other evidence, there is risk of contamination or misinterpretation of trace evidence, and the way the strength of a match or near match is communicated to a judge or jury.
What I found most interesting about this chapter was psychological bias in fingerprint identification. A person would think that fingerprint identification is set in stone, with possible technical errors. Human error is something that I had not thought about until reading this chapter. If a fingerprint examiner gets information about the suspect beforehand, this could affect their findings. Information given can trigger confirmation bias, or an inclination to search out evidence that confirms our beliefs and to ignore evidence that contradicts our beliefs. So if a fingerprint examiner is told that the suspect has already confessed, this could lead the examiner to finding the fingerprints match, instead of finding a non-matching pair, based on prior knowledge.
At the beginning of the chapter, the story of Brandon Mayfield being wrongly accused of murder because of false fingerprint analysis was told. I was interested to look more in depth into the story, and after further research I think it is scary that even fingerprints can be false. I found it interesting because after the FBI had realized that the fingerprints were not Mayfield’s, the out-of-state examiner was decertified and lost his job, but not the two local officers. Mayfield had spent more than 2 years in prison before being released.
http://www.cbsnews.com/stories/2003/07/16/60minutes/main563607.shtml
The courts are great consumers of forensic
identification evidence and if they refuse to allow all but reliable evidence, we would be likely to see far more effort to evaluate the validity of forensic techniques.
More often then none, evidence can and has been tampered with in some cases to were it was so bad that the perpatrator gets off of the crime they committed because proper precautions werent made.
Trace evidence is really important to a case and trial because this actual evidence could actually convict or set a person free of the crime committed. But following some measureable quality that is unique for every person, which means distinguishing one human being from all others
The courts are great consumers of forensic
identification evidence and if they refuse to allow all but reliable evidence, we would be likely to see far more effort to evaluate the validity of forensic techniques.
More often then none, evidence can and has been tampered with in some cases to were it was so bad that the perpatrator gets off of the crime they committed because proper precautions werent made.
Trace evidence is really important to a case and trial because this actual evidence could actually convict or set a person free of the crime committed. But following some measureable quality that is unique for every person, which means distinguishing one human being from all others
I am still waiting on my book.
This chapter was about the different forms of forensic identification and the threats to that because of technology and error. Technology and computers are gradually taking over what normally a human's job would be. There are always risks, however. Evidence can very easily be contaminated or misinterpreted, so it is hard to trust at times. Also, a large factor when it comes to tracing evidence is portraying that evidence to the jury; since they are the people who make the most important decision. There are very strict rules and procedures set in place for forensic identification, but there will always be doubts.
The most interesting thing and most surprising to me was the bias that came alone with DNA evidence. The part where they say the jury was more likely to say two fingerprints matched after seeing gruesome photos surprised me, but also did not. I can understand the difficulty of having to see those images and wanting justice, but what is the point if it is not the truth. How reliable is evidence if the jury's opinion is biased? This just pointed out more to me how psychology and law really are hand-in-hand. As different as the two are, you cannot have law or crime without psychological occurrences. Why the jury responds how they do and feel the emotions they feel is psychology in itself. I think DNA and forensic identification are very important and useful, but I do also believe that they can be as unreliable as the person's word. This website sums up that jurors go in with their beliefs and make decisions based on that, not by evidence presented.
http://pensacola.injuryboard.com/medical-malpractice/juror-bias-affects-trial-outcomes.aspx?googleid=200874
There are many different forms of forensic identification. Over the years, forensic identification has only become more advanced and more important than ever. Forensic ID started back in the 19th century when measuring one's body was the way of distinguishing one human from another. Eventually, this technique was put to rest with the discovery of how fingerprints are a better indicator. Fingerprints have become a popular way of telling one human from another, and professions specific to fingerprint knowledge have been created. Along with the importance of fingerprints, DNA has gained similar importance. Both DNA and fingerprinting are valuable methods of determining one's identification, however they both can have negative downfalls. Computers and technology, along with science, have brought reliability to the usage of fingerprints and DNA in legal matters, yet certain grey areas still remain.
I was surprised to see the question marks raised by using forensic ID, especially in the courts. Granted, I knew there were certain circumstances in which forensic ID was questioned, but I saw it as more of a black and white topic. To me, the DNA/fingerprints either match or don't. However, those grey areas can lead to a different outcome than what I expected. I would like to learn more about this specific issue and how the use of DNA/fingerprints isn't always looked upon as the best method of proving one innocent/guilty.
Here is a link I found relating to that issue.
http://library.thinkquest.org/19037/court.html
Throughout Chapter 4, the most interesting thing I read about were fingerprints. I have always thought that fingerprints and their uniqueness were interesting. I am surprised to learn that fingerprints really are not as accurate (when be examined or matched) as one would think. It was surprising to lear that real people, and not just computers, contribute to fingerprint testing and matching. I found it unfortunate that you cannot count on fingerprints to catch perpetrators as easily as I previously believed. It was also disappointing to learn that many people have been convicted because of false fingerprint matching and no access to information that DNA can give us now.
I am highly interesting and want to learn more about fingerprints and ways they can be tracked. I also find it interesting that only 5% of people have "arched" fingerprints.
http://www.odec.ca/projects/2004/fren4j0/public_html/fingerprint_patterns.htm
This chapter was about forensic identification, more specifically DNA and fingerprints. The book talked about tracing evidence and identifying people by using their DNA and fingerprints and how a crime case can go cold if there is not enough evidence to convict anybody.
I thought that it was interesting to find out about tracing evidence and how that actually works from a professional. DNA and forensic techniques have advanced throughout the years and they have become more and more important as we age. Previously, I thought that once fingerprints were found left on something from a crime scene, then that person is automatically caught. After reading this chapter, I learned that it is a much more complicated process than that and sometimes it doesn't even work like that. DNA and fingerprints will not always solve all things and sometimes there can even be negative downfalls after finding evidence. I thought that all of the different techniques were very unique and it surprised me how much error and bias there could be. I also thought that it was interesting that even with DNA and fingerprints, a person could still commit a crime and sometimes get away with it.
I would like to learn more about the physical trace of evidence and how detectives use that when trying to solve a case. Here is a link I found that has more links attached to it about human and product identification http://www.forensicpsychology.net/resources/forensic-identification-resource-library/
Chapter 4 is about the different kinds of forensic evidence that are collected from a crime scene. The main goal of a forensic scientist is to find trace evidence that could have come from one and only one person. Trace evidence is important but is not always as reliable as we think it is. It’s also very easy for this evidence to be portrayed or introduced in a way that sways the viewer’s opinion of it.
I found it interesting that expert witnesses rely on statements like “the basis of my opinion is my 20 years of experience as a forensic examiner” to persuade juries or judges. Since most people have a limited knowledge of the science of forensics, we aren’t very good judges of the reliability of the evidence and we rely on the expert witnesses to give us factual evidence. It’s unnerving to think that we can be so easily persuaded into thinking highly of someone’s scientific opinion based simply on their career experience. While that is a factor in what information should be relied on or believed, it’s not the only factor to take into consideration. The reliability of the forensic evidence being presented needs to be taken into account. In order for that measure to be trusted it must be reliable and valid. Unfortunately, some measures can be reliable without being valid and when this occurs the subjectivity of the person evaluating or presenting it is allowed to effect the presentation.
The most surprising thing in this chapter was the study that was done with the professional latent print examiners. They identified fingerprints as clear and definite matches. Five years later they were given misleading information that those same fingerprints were the ones that led to the mistaken identification of a bomber. The examiners then had to decide f the fingerprints were a match and 3 of the 5 changed their opinions and said the fingerprints didn’t match. It’s surprising how easily these professionals could be affected by information given to them about the fingerprints leading to “confirmation bias.” I looked up more information on biases while researching or examining fingerprints. I found an article about the Brandon Mayfield case that discusses possible theories explaining why the fingerprints were wrongly matched: http://www.nacdl.org/public.nsf/0/3419bfeee2f5c72c85256ff600528500?OpenDocument
Another article talks about “unintentional bias” that can ruin the results of a fingerprint analysis: http://www.miller-mccune.com/legal-affairs/bias-and-the-big-fingerprint-dust-up-3629/
i just got my book i should have chapter one and four in by friday
In chapter 4 it talked about trace evidence, how to identify where evidence came from, when trace evidence matches, and the difficulties of matching trace evidence. Many people think evidence is so easy to match but in reality it is very hard and the accuracy of it matching is hard. I thought finger prints and DNA was a for sure match but I learned it is not. I guess I watch too much TV. TV makes it seem so easy.
The most interesting thing I learned and that kind of scared me was when they did the study on fingerprints and took ten pairs of prints and asked fingerprint experts who declared them to be a match and had them look at them again not knowing and over half of them declared they were not a match or that they were not sure. Only two experts were for sure they were a match like they declared the first time.
I also thought it was interesting when they talked about anthropometry. The way they described it in the book sounded interesting. I wish the book talked more about why measuring 11 parts of the body help determine who the perpetrator was in a crime scene. I chose to look more into anthropometry and his is what I found. Anthropometry helped determine risk of disease. It is still used today to help determine risk of breast cancer and cardiovascular disease. I could not find how they used it in court to convict someone. This might be why it is not significant in evidence today.
http://www.history.ox.ac.uk/ecohist/synopses/1c_demography/anthropometric_history.htm
http://en.wikipedia.org/wiki/Anthropometric_history
http://en.wikipedia.org/wiki/Anthropometric_history
Forensic science is the collection, analysis, and interpretation of physical evidence. The way in which we collect this information and evaluate it is changing greatly. Certain methods of collecting evidence have been classified as ineffective because of new technology and greater knowledge of the forensic field. Matching bullets and handwriting specialists are now considered to be forms of pseudoscience and are not a viable source of evidence. DNA and fingerprinting are now the most important ways of collecting evidence in today's society. DNA is one of the greatest scientific breakthroughs of the 20th century for good reason. DNA are tightly coiled strands that carry the genetic instructions for all living cells and are unique to individuals. DNA can be extracted from blood, semen, saliva, or skin cells and if DNA matches a sample it is a match to a certain degree.
I was most surprised by the problems that remain in forensic identification even if technological fixes are found. I understand that like everything there are some forms of error in forensic evidence but I was taken back by the fact that technology will not fix these errors. The three problems are (1) weak scientific foundation for many forms of trace evidence, (2) risk of contamination of trace evidence, (3) the way the validity of a “match” is communicated to a jury.
I decided to research biometrics because it is the identification of a person based on measurable anatomical traits and I found that to be very interesting. There are many forms of biometrics including palm print recognition, fingerprinting, hand geometry, iris recognition, and face recognition. Hand geometry is the subcategory that I find most interesting because it is something I didn’t know a lot about. Hand geometry began in the 1980s and includes measuring the length, width, and surface area of the hand. Hand geometry includes analyzing 31000 points and taking 90 measurements. Hand geometry is widely used yet I have heard very little about it.
http://www.biometrics.gov/ReferenceRoom/Introduction.aspx
Any sort of evidence can be very important in any case. Although this is so, sometimes evidence can be very misleading and unreliable. There are multiple types of foresic identification including DNA and fingerprints that can be used against people in trial, in which it is important to have accurate evidence since reliability and validity are big factors.
The most interesting thing that I learned from this chapter was learning that the chemical compounds relating the bullet at a crime scene to the bullet that the suspect may own, may be the same but does not rule out that this person committed the crime. In fact, thousands of bullets could have the same chemical compounds if made at the same time in the same factory. I have always had this notion that we could match these in order to solve the case. It wasn't until 2004 that the bullet matching evidence did not work with the courts anymore.
The one thing that really surprised me was the story in the beginning of the chapter that had to do with the March 11, 2004 bombings in the Madrid subway. I couldn't believe that a senior FBI fingerprint examiner would make a mistake that would invade the privacy of an innocent person, then actually arrest him and take him to court, all the while later finding an Algerian man living in Spain that may have detonnated these bombs. I think it is crazy that mistakes like this can happen.
I really want to learn more about how fingerprints can be used as evidence against people. I really am interested in the different ways that we may find fingerprints also.
http://www.fbi.gov/about-us/cjis/fingerprints_biometrics/recording-legible-fingerprints/takingfps
Chapter 4
I found this chapter very interesting for two reasons, 1. Trace evidence is not always accurate or attainable, 2. Expert testimonies are given through requirements. I found it very interesting that fingerprint examiners are limited in there testimony to only giving three conclusions. The first is that a the print is inconclusive, meaning there is no way of proving the print is a match. Secondly the print is suspected as a source of a print, and third the print is the source of Individualism. The chapter also explains how other professions have there own guidelines to giving testimonies. Also interesting in the chapter is the fact that most experts in the field of handwriting are more prone to errors.
I found it very interesting at the beginning of the chapter the part about the lawyer’s prints being mistaken for those of another persons. I would like to learn more about the whole process of finger printing as well as advances in the field. I read up on biometrics and how it is possible to cheat finger print identification as well as how technology is being advanced.
This is a link on Biometrical fingerprinting
http://cryptome.org/fake-prints.htm
Chapter 4 was mainly about the different methods that can be used to match different pieces of evidence from crime scenes. As found out through reading this chapter most of these methods are still unreliable and are not widely accepted. Even though DNA and fingerprints are the most widely accepted trace analysis there are still many flaws that go along with them. The most interesting and surprising thing that I learned came all at the same time when the authors wrote about class characteristics, and also individual characteristics. I found this interesting because when they talked about leaving foot prints at the scene, I thought it would probably be pretty hard to track someone down by the type of shoes that they were wearing because they could just dump the shoes. Then in turn it would be hard to use individual characteristics (scrapes or wear patterns) to say that person had that shoe on if the shoes werent in their possession.
Something that I wanted to research more about were cases that fingerprint evidence didnt seem overwhelming and to see whether or not the person on trial was still convicted. This article was very interesting http://news.bbc.co.uk/2/hi/programmes/panorama/1426720.stm. I think fingerprint evidence is a tough issue to deal with because the chances of finger prints matching to someone else in the same area is unlikely but there is still that possibility that they could be somebody elses.
Chapter four is about evidence that can be used from a crime scene. Trace evidence is usually the most important and most reliable. This evidence can include fingerprints, hair, skin cells, and fiber from clothing. The goal is to find some piece of evidence that can be linked to only one individual. Though fingerprints are unique to each individual, there is still room for error and people are still falsely convicted because of this.
Something that surprised me the most was that fingerprints are never 100%. I always thought that that was one for sure way of knowing that a person was innocent or guilty. It’s shocking to me that there can be any sort of error and bias in something like that.
I decided to look more in depth at the different types of fingerprints. There isn’t just loop, whorl, and arch for identifiers. There are different sub categories to each of them. Loops are the most common counting for 60-70% of the population, then whorls in 25-35%, and lastly arches are only in about 5%.
http://www.odec.ca/projects/2004/fren4j0/public_html/fingerprint_patterns.htm
Chapter 4 was way more interesting than chapter 1. This chapter focused for more on how trace evidence is important in the court but, how it is also unreliable. I didn't realize that if the perpetrator didn't put enough pressure or had too much pressure on a single fingerprint then the print could be unreliable. This chapter also explained how fingerprint evidence came into play. I studied fingerprints in AP Bio in my high school, so fingerprinting was a review but it's still fascinating how theres 3 different techniques to identifying a fingerprint (loop, whorl, arch).
One thing that I found interesting was errors in forensic evidence may be limited because of technological advances. I really hope that scanners and computer programs advance because it would be really nice for jurors and attorneys to identify people by the smallest identification. I don't know how updated this article is but it helped with my understanding of how people rely on fingerprints. (The statement about the bank is what I'm referring to.)
http://stephan.grandpre.net/fingerprinting.html
This chapter is principally about the different kinds of physical evidence that are admitted in the courtroom and the flaws and problems associated with each type. The chapter explains that DNA evidence is the most reliable of the different types of trace evidence, but that even it is not without flaws. There is often a public perception that trace evidence such as fingerprints lifted at the scene, or dental impressions left by a suspect are concrete physical evidence. This chapter points out the many flaws that are inherent in most if not all of the forms of trace evidence utilized today. For instance, the book points out that the majority of jurors polled found finger prints to be concrete evidence in a case. The authors point out, though, that not only are our misconceptions about the uniqueness and reliability of finger prints wrong but that their intrepetation is largely based on the relative experience of technicians rather than an absolute, quantifiable science. These public misconception and interpretation errors are common to virtually every type of trace evidence, even DNA to an extent.
The most interesting thing that I learned is that evidence that in movies is portrayed as being iron clad and completely incriminting is in fact largely based on interpretation. For instance, the book talked about the chemical analysis of bullets and the microscopic analysis of the groves left on bullets by the muzzle of the barrel, that in popular media are often used to "nail" the subject, but in reality are based on science that is not only disputable but in some cases is simply wrong. Criminal cases are not nearly as open and shut as I had always thought. There is so much ambiguity in the evidence that verdicts are much more a product of "acceptable probability" than black and white absoluteness.
What surprised me the most in this chapter was the illustration of the FBI case against Brandon Mayfield. The FBI was 100% certain that he was behind the bombing in Madrid, but they were proven to be completely wrong by the Madrid police. If the most sophisticated crime fighting agency in the US can be so blatantly wrong in interpreting physical evidence, it makes one wonder how often errors like this occur in criminal proceedings.
I would like to learn more about the number of people who have been wrongly convicted in the United States. It would be very interesting to see some statistics on how often innocent people are punished for crimes that they didn't commit.
The following link is an article I found discussing some of the difficulties in using ballistic evience in court and a study that has been done in order to improve the reliability and accuracy of certain ballistic tests.
http://www.justnet.org/TechBeat%20Files/Study%20Compares%20Gun%20Barrels%20and%20Bullets.pdf
Great job with the summary and interests, just make sure you report/summarize your link! :)
The title of Chapter 4 already gives away much of the context of the chapter: “The Psychology of Forensic Identification: DNA, Fingerprints, and the Physical Trace Evidence”.
First, all evidence of the crime scene has to be collected in order to start with the forensic identification. This is the process in which the evidence is analyzed in order to find suspects or the perpetrator. The forensic identification uses biometrics to do so. So called trace evidence are compared to samples in order to find common sources. One of the most common identifying methods are fingerprints nowadays. Compared fingerprints can have following outcomes: inconclusive, excluded as source of the print,and individuation, which means that the print and the source are matching. However, fingerprints are not put into a computer that searches through databases. Fingerprints are examined manually. Since 1988 DNA from blood, saliva, semen, or skin cells is used as evidence in U.S. Courts and serves as a unique identification system. Alleles and there loci are compared. Errors might occur due to judgment of the analyst if the samples are not a perfect match. Other types of forensic identification use comparison of bullets, of tools and teeth.
Important is that many jurors have difficulties with statistical statements and probability.
Very interesting for me was to read more about the CSI Effect. Jurors expect too much from the forensic evidence because they have seen unrealistic evidence analysis on TV shows. Before this class I did not know about this effect, but I find it very comprehensible.
The most surprising fact I read in this chapter was that there are no fingerprint computer databases, but that it is the job of human examiners to compare fingerprints.
During my search for additional information I found out about DNA technologies used in the forensic identification such as Restriction Fragment Length Polymorphism (RFLP), which was one of the first used techniques. Another interesting technique is the Y-Chromosome Analysis, in which only the male Y chromosome is analyzed. This is used when there are several male suspects involved.
(http://www.ornl.gov/sci/techresources/Human_Genome/elsi/forensics.shtml 9/6/2011-9:22pm)
Also on this website I found interesting links to DNA database projects around the world.
Chapter 4 discussed some different forms and ways of collecting forensic evidence, including DNA, fingerprints, bite marks, tool marks, and bullet striations. This chapter also discussed that some forms of trace evidence, bite marks, tool marks, and bullet striations, are not as reliable as many think and are often misinterpreted. Chapter 4 also discussed how even though forensic identification someday may be minimized by technological advances, three fundamental problems will always remain. These problems include weak scientific foundation, the risk of contamination of a crime scene as well as personal misinterpretation, and finally, the way the positivity or strength of a close match or match is presented to the court. There is more of a stress on proper collection of evidence than the other two, including proper and cautious procedures as a specific part of forensic identification. As I stated earlier, this Chapter also discussed the weaker points in trace evidence, but it also stated that the courts are the tools that can begin to allow only the most reliable evidence. If technology can advance and become more percise in an attempt to catch the perpetrator, the courts, as the consumers of forensic evidence, need to allow only the most reliable evidence, and disregard unreliable techniques that our society has advanced from. If this is done, more true perpetrators will be caught, and true justice can be served.
I thought all of Chapter 4 was extremely interesting; however, I found the section, "Techniques of Weak or Unknown Validity," to be especially interesting, more specifically the section on bite marks. I must admit, I am a Law & Order, CSI, and NCIS junkie and I always thought that bite marks would be a pretty solid way of determing the perpetrator. However, Chapter 4 stated that 63% of the time dentists identified an innocent person as the source of bite. This figure blew me away!
I would like to learn more about bite marks and how peoples teeth can link them to a crime scene. I always assumed teeth and bite marks were as reliable as fingerprints, and I would like to research a little bit more about it myself.
The first link I went to to learn more about bite marks was very interesting. I never knew that Ted Bundy's case included a bite mark to help convict him! This webiste also talked about the controversy of bite marks and how many cases are now being overturned. It talked about the elasticity of the skin and how it can lead to misinterpretations of whose teeth actually sank into the victims flesh. It also discussed how forensics would go about trying to analyze bite marks. It was extremely interesting.
The second link I looked at dealt with the argument on the individuality of human teeth. This website discussed the foundation of dental identification as well as a pretty interesting study performed at UCLA on identical twin dealing with the degree of depth necessary to test a bite mark between the twins. Depth of a bite mark was something I hadn't even thought of, but now I think it would have a lot to do with accuracy in determing the correct source of the bite. This website went on to talk about the history of bite mark analysis and it was overall very interesting and eye-opening.
Links:
1. http://karenlotter.suite101.com/taking-a-look-at-human-bite-marks-a49950
2. http://www.forensic.to/webhome/bitemarks/arguments_on_the_individuality_o1.htm
Lindsey Fails
response from TA:
Extremely good post! You hit on all the points you were supposed to and made it easy to understand. Good explanation and links! :)
Book was supposed to be here today according to Half.com, but still isn't!
This chapter can best be summarized as a discussion of how the physical evidence aspects of the criminal justice system are affected by psychological principles. This chapter also includes a synopsis of the various types of physical evidence and how it is collected, processed, and presented. According to this chapter, the dependability and reliability of physical evidence has been greatly exaggerated over the years. In reality, even the slightest change in the environment can render any physical evidence unusable. For example, a minor change in pressure can cause a finger print to be unable to be compared and matched. There is a widespread misconception/over reliance on collectible physical evidence among the general public. This creates the CSI effect that we discussed in class.
One of the things that I find most interesting in this chapter was the passages about DNA evidence. Prior to reading this chapter I had a basic knowledge of the concepts of DNA evidence but I was not aware of many of the specific facts described int his chapter. Just a few of the facts that I learned about DNA from this chapter include; the two scientists, James Watson and Francis Crick, who discovered DNA, the length of time between the discovery of DNA and the realization of the potential uses of DNA in the criminal justice system, and the existence of RMP's (random match probabilities).
I decided to further research random match probabilities (RMP's) and their uses in the criminal justice system. Below are the links that I found to have the most complete and reliable information.
http://www.bioforensics.com/conference/RMP/index.html
http://www.dna.gov/basics/analysis/steps
http://dimacs.rutgers.edu/Workshops/HumanPopulation/Slides/Song.pdf
Ch.4 is about all different kinds of evidence on a crime scene, like fingerprints and DNA.
In the section of reducing error and bias, I really enjoyed the part about double blind. A good example of blind effect is “the placebo effect” which is when a dr. is testing a drug and has 2 groups one with the drug and one with a placebo, as the participant does not know there are difference in the drugs, which reduces the risk of bias. Which is really important when dealing with a case as someone with a bias, lets say a family member and so they are not as credible when they testify. Now a double blind is a little bit crazier, back to my earlier example on the Dr. administrating the pills. The Dr. doesn’t know which patients are getting the placebo or the pill, to make sure that they don’t subconsciously tip the patient of the pill that they are getting. So basically if you don’t trust your workers, or just want to be careful you would take this extra… precaution. A good example; during a police lineup it is advised that someone not connected to the case to conduct the lineup, as they have no bias so they can not ask them leading questions that subvert the independent memory.
http://www.experiment-resources.com/double-blind-experiment.html
This chapter explained all about the discrepancies in evidence found in a crime. Some of the things they stressed were about fingerprints, DNA, trace evidence, and what all of these possible discrepancies mean to the jury. When they talked about the fingerprints and how it wasn't as reliable as it seems to be on television, the two points I felt it made were that fingerprints can be distorted according to how much force they used when pressing down and what the surface they had touched was like and that even though there are many points in the fingerprint that match it may also be true that 80% of other americans have some of the exact same points. The DNA was similar to those findings about the fingerprints because DNA may have some matching alleles but not all exactly matching to the ones found at the crime scene. This chapter stressed that the probabilities of all the supposed "matching" evidence is extremely important to pay attention to because if an analyst said there is a 4% chance that the prints do not match, some jury members would either think that there is a 96% chance that that is the perpetrator and others would think that their are potentially millions of other people out there who has similar fingerprints or DNA.
The most interesting thing I learned is that many many people could have some of the exact same points on their fingerprints as you do and that knowledge could really change the outcome of a trial if analysts say there is a 96% chance that person is the perpetrator. Something surprising I found was that it's not actually a machine that you put fingerprints in that tells you if it matches or not. It's actually a person who sits in front of the screen and tries to match up key points on the print to see if it could be a potential match. The whole process is much longer than what is shown on television.
What I would like to learn more about is just about fingerprints in general because there was so much that I found to be surprising about them. On the website I found, it explained there are about seven types of fingerprints that are distinguished by the type of "swirl" they have. They are the arch, tentarch, loop, double loop, pocked loop, whorl, and mixed. If I had to describe mine I think they would fall into the "loop" category. Another thing I learned is that even identical twins do not have the same fingerprints which to be perfectly honest I always thought they did.
http://edward.nygma.tripod.com/fingerprints.htm
I am still waiting on my book. It should be in by Thursday I am hoping. When I get it Chap 1 & 4 assignments will be done asap!
Summary: Chapter four discusses how biometrics has evolved throughout the years, as well as trace evidence, and how it is perceived, how facts or lack of facts can be misconstrued and eventually effect judgement of experts, authorities and the jury.
1&2: One of the most interesting/surprising things I read was discussed on pages 88 and 89 where the psychological biases in fingerprint identification were discussed. This seemed so out-there to me, because I had always thought of fingerprints to be rather substantial evidence, very scientific, and not easily misenterpreted. (Must watch too much CSI). The studies showed how examiners identified prints differently, because they were effected by previous misleading information. The first pages of the chapter also discussed how something so seemingly factual as fingerprints are not completely immune to psychological biases when an innocent man (Brandon Mayfield) was almost sent to jail when his fingerprints combined with some negative stereotypes put him in a guilty position. Fingerprints used as evidence could be completely misinterpreted. It is clear that what may appear to many as being rather factual evidence could send an innocent person to jail or free a guilty person depending on psychological bias. This can be a scary thing when jurors are often more likely to be persuaded by fingerprints than eyewitnesses or alibi evidence(95).
3)I am interested in learning more about fingerprints and how exactly they are used as evidence in court/ how reliable are they. Here are a few links I found that furthered the discussion of history of fingerprints and how they are used in court.
http://www.bxscience.edu/publications/forensics/articles/fingerprinting/r-fing01.htm
http://www.forensic-evidence.com/site/ID/ID00004_2.html
Book should be here in the next few days. Once it arrives I will get chapter one and four completed and turned in right away.
Trace evidence is supposed to make it easier to figure out who committed a crime, and make people more certain that they are responsible. I think people rely too much on DNA and fingerprints. DNA can be degrated, and we do not know for sure that each fingerprint is individual. This chapter talked all about DNA, fingerprints, and what they meant to juries.
Juries seem to take expert witnesses for their word, which shows me that judges need to make sure that they are qualified to testify. Fingerprints have many different characteristics, and some may match to another person, and if you just looked at those you may think the other person is responsible. People can also burn their ridges off, which would make it impossible to tell who committed what crime, this is highly unlikely, but it does happen.
This chapter made me wonder if there is a tendency for people to have similar fingerprints. Most of my fingerprint details are ridges, except for one which is halfway between a ridge and a whorl, and one which is an arch. Is this a coincidence? Does it have to do with how we develop in the womb? Does one pattern mean there was a more condusive enviornment than others? I feel like there is still a lot we don't know about fingerprints.
DNA is also not one hundred percent foolproof. Identical twins have identical DNA. This makes it nearly impossible to tell which twin committed a crime, unless one admits to it or blames the other. DNA can also be degraded, in which case it is harder to match it to a suspect beyond a reasonable doubt. There can also be errors in the lab either with the technicians or machinery.
This chapter was about trace evidence and its continual scrutiny in the judicial system. Trace evidence such as fingerprints, hair, fibers, bite marks, etc. is all very unreliable for several reasons. Evidence can be collected poorly or contaminated before it reaches the lab for analysis. The examiner can also be biased be situational pressures or misreading the sample. Not only can things go wrong with the evidence that is collected, but it has been determined that the probability the particular piece of evidence be narrowed down to one person is really low. There are a lot of characteristics the general population shares in fingerprints, the shoes and clothes they wear, and the glass in their windows so it is hard to determine where something came from with 100% certainty.
The most interesting thing about this chapter was the section about pseudoscience, in particular handwriting analysis. The book mentions the rate of handwriting error can range from 40%-97%. Many people disguise their handwriting during a crime, it can be influenced by drugs or alcohol, or someone can have an injury that flaws their writing.
What surprised me the most in this chapter was that DNA was discovered in 1953 but it took 30 years for them to realize the “forensic potential” it contained. For that reason, DNA was not introduced into the courts until 1988.
I would like to learn more about false positives. The book mentions false positives can happen when an expert concludes that match exists when it really does not. The rate of this crisis is very difficult to determine and I think there needs to be more research done about it.
Additional information I found on false positives was mainly in the field of medicine, more specifically HIV testing. A way to correct this problem in both the judicial system and medicine would be to get more than one opinion and get a test done more than once. That way if you get the same results, there is a higher probability that the sample is reliable and accurate.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC84219/
I am waiting for my book it should be here tomorrow so I will get both chapters done then.
Chapter 4 is mainly about trace evidence and different kinds of forensic identification which can be used to link trace evidence to a suspect. Some of the different kinds of forensic identification used today are fingerprinting, DNA, bullet striation matches, etc. The chapter also tells about the wide range of errors that could occur from processing the evidence (contamination, mislabeling, etc.) to the forensic analysts viewing the evidence (not having enough training, having biases such as confirmation bias, etc.) However, they are trying to come up with ways to reduce the amount of errors and the potential for them. For example, they are invoking more training for analysts and to have them do proficiency testings.
The most interesting thing I learned from the reading was that there used to be an identification technique called anthropometry and that it was used for a couple decades. It was also interesting to learn that some people may have almost identical measurements when it comes to using anthropometry. I was surprised to find out that comparing bullet striations is considered a weak technique. I was unaware that they didn't have guidelines/standards on bullet striations in order to declare matches.
I would like to learn more about psychometrics. Psychometrics started out just measuring intelligence. Later, psychometrics started focusing on personality testing. One of the most well-known personality testing instruments is the Myers-Briggs Type Indicator.
Here are some links that provide more information about psychometrics:
http://www.assessmentpsychology.com/psychometrics.htm
http://www.personalitypathways.com/type_inventory.html
1. Chapter four is about forensic identification and the ways we can determine this, whether it be through DNA, fingerprints or physical trace evidence. This chapter also discusses the flaws in such things as fingerprints, bullet fragments, and the different scrape marks from weapons. This chapter also talks about the jurors, and how the attorneys are able to word statistics differently to sway the jurors in their favor. Bias also is a big issue covered in this chapter and how it can affect people’s decisions, whether it is the jurors, the investigators, or the examiners.
2. The first thing that really surprised me was the idea that we are not 100% sure that no two people’s fingerprints are the same! The book said that there are about 6.8 billion people in the world, most with 10 fingers; therefore, there are over 68 billion fingerprints. This is a scary thought to think about when a defendant can be found guilty of a crime on only the evidence of a fingerprint! Another thing I found alarming was how easily swayed some jurors could be. The fact that jurors are picked at random (even though they are evaluated first) it is still unsure if they are educated enough to be able to pick apart statistics for what they truly are and not just take them at face value.
3. The topic I wanted to research a little bit more into was the issue of the “CSI Effect”. These shows do make everything seem so glamorous! Everyone is always sharply dressed, the labs are always spotless with the latest (un-invented) technology, and the cases are almost always solved in a one hour episode! The idea that jurors get the impression from all these CSI shows that “all cases are solvable by highly technical science, and if you offer less than that is it viewed as reasonable doubt (92) is a scary one.
Here are a couple links I found that pertained to this issue:
http://www.nij.gov/journals/259/csi-effect.htm
http://www.usatoday.com/news/nation/2004-08-05-csi-effect_x.htm
Before reading this chapter, I was always under the impression that trace evidence was compelling evidence. However, trace evidence has its many flaws and inherent problems. 1. There is weak scientific foundations for many forms of trace evidence, 2. Risk of contamination or misinterpretation of the trace evidence, 3. The way the strength of a "match" or near match is communicated to a jury or judge. These are problems that may only be solved with further technological advances.
The story of Brandon Mayfield and his apparent involvement in a Madrid bombing surprised me the most. One of the best investigation agencies in the world (the FBI) was unable to correctly identify a correct match when viewing fingerprints found on the detenation bag. Not only did they make an error while fingerprinting, they were 100% sure that they had found the correct suspect. Enough so that they arrested Mr. Mayfield based on thier faulty trace evidence. It makes you wonder how many innocent people are currently sitting in prisons based on trace evidence that may be incorrect.
While reading this chapter I was repeatedly asking myself about these innocent prisoners and wondering how many innocent prisoners there really are so I decided to look into this topic further. In the last few decades over 200 people who have been sentenced to death have been found innocent of their crimes. Even though DNA played a role in thier exoneration it also plays a role in putting many innocent men and women behind bars. Simply being near the scene of the crime can cause you to leave trace evidence and eventually become a suspect. It is scary to think that we live in a country where the system can incarcerate innocent people on a daily basis based on insufficient trace evidence.
http://www.ehow.com/about_6661199_effects-comes-down-capital-punishment.html
1) This chapter was about forensic evidence and the reliability of that evidence. The chapter starts out by showing an example of how evidence can be misinterpreted by authority figures then moves on to show different ways of identifying suspects in criminal cases. The chapter then moves to a more statistical approach in identifying suspects in criminal events. Even with all of these statistics involved you can never be certain of anything.
2) The thing that surprised me the most was how in the beginnning of the chapter with the bombing incident the FBI took into account the fingerprints and had "100% certainty" that the fingerprints belonged to the guy they had suspected. Even with warning from the Spanish police force that they had the wrong guy, the FBI was too stubborn to hear them out and almost convicted the wrong person.
3) I would like to learn more about the CSI effect in courtrooms. I found this very interesting how jurors have the belief that there are more resources out there than possible and that jurors demand too much evidence that couldn't possibly be recovered. Here are some links that further this topic.
http://www.nij.gov/journals/259/csi-effect.htm
http://articles.cnn.com/2011-07-06/opinion/hoffmeister.anthony.jury_1_csi-effect-jurors-crime-scene-investigation?_s=PM:OPINION
I did Thursday’s assign on Tuesday, so I am doing Tuesday’s tonight. Sorry. The thing that interested me most about Chapter 4 was when does a trace match a source. This interested me because I always wondered if they had a fingerprint, how they match it. They couldn’t just run it through a fingerprint system that said who it belonged to. The tv shows (which I don’t watch too much) make it seem like if you have trace, whether it be a bullet case or fingerprint, the case is closed. The book talks about how they found that bullets from the different boxes may be extremely similar in their chemical makeup. I was also surprised to read about how handwriting evidence is really not very accurate at all. The book also talks about how the simplest approach to finding a match is a nonstatistical qualitative strength of a match. This is measured by how weak, moderate or strong a match is. I always thought it was a perfect match or not a match at all; not based on a ranking system.
The other thing that caught my interest is how DNA evidence is used. I again, thought it would be a match or not, and the book talks about how it is based on alleles, and if DNA tests yield ambiguous results, then some of the alleles may match perfectly, but others not. If this happens, it is all based on the human analysis. Crazy how things aren’t as cut and dry as we always think they are.
Learning about fingerprints was interesting too. Of course, while reading it I found out my prints are more of an arch, rather than a loop or a whorl. The book also says that it is very difficult to distinguish between similar fingerprints, regardless of the fact that no two prints are the same.
1. This chapter in the book is about Forensic Identification. Like the fingerprints at the scene or DNA and Physical Evidence. At the beginning of the chapter they start by saying that there is no way to commit a crime and not leave evidence or to not take evidence away from the crime scene. It can be as little as a hair fiber to your shoe footprints or even blood or skin cells. It talks about the way physical evidence can be used and what the evidence is that is at a scene that they look for. I really enjoyed reading this chapter more than the first one. Feels like are finally starting to get into the good and interesting stuff.
2. I found as I was reading this chapter that the fingerprints section was the most interesting to me. There are different ays they figure out the fingerprints. Each fingerprint has a particular design or pattern on it and no two are alike. They look for certain places were the fingerprint loops, arches, an were there is a whorl. There are more patterns and that is how they decide what fingerprints match up. Then what I found was interesting was that up until 2004 they did use bullet matching evidence in the courts. And now after 2004 they are not in favor of using that evidence in court anymore.
2. I want to learn more about the fingerprints section. I learned that in real life its takes more than a few seconds to just match up the prints from a scene to a person and sometimes it doesn't even match up. After they powder the prints and put them into the computer that is when it narrows down the potential suspects. But the computer doesn't just match one finger print up to the exact person like the t.v shows portray. They have to get a human examiner to come in a they will be the one to look at the narrowed down fingerprints and they determine what one matches. If the prints also arent in the database then there is no way to match a print from the scene to a print in the database.
http://www.bxscience.edu/publications/forensics/articles/fingerprinting/r-fing01.htm
1. Chapter 4 is about all the different problems and errors that occur with forensic identification. The thing I found most interesting was the section about psychological biases in fingerprint identification. I just thought it was interesting how flawed and bias fingerprinting is, and how easily something at one time that was clear and obvious can flip a few years later to a no match.
2. The thing that surprised me the most was once again how finger prints and forensic evidence can be so bias, and ultimately very flawed. I knew it wasn't as easy as they made it look on t.v. but I didn't realized how flawed and how easy it is to alter as well as contaminate forensic evidence.
3. Something I would like to learn more about is if finger printing is such a bias study, why is it looked at as such a powerful evidence weapon in most cases. In short why are fingerprints deemed as so important in cases if even the "professionals" that look at the prints are supposed to be indifferent to the case hold biases according to their knowledge of the case. There are more effective ways of fingerprinting such as digitally opposed to visually. Once everybody uses digital fingerprinting I think finger prints would be considered a more credible piece of evidence, just for the reason a computer doesn't hold biases but people do.
http://www.slate.com/id/2101379/
This chapter was about trace evidence and its validity; not only the validity but the terms and ways in which evidence is presented in court. The way in which they present the evidence has a lot to do with the understanding and interpretation of the evidence.
The most interesting thing I learned was that although DNA is the most reliable source of a identification match it was also the most scrutinized. This means that all the other ways to create an identification match such as fingerprints or handwriting analysis, which are less accurate, needed less “proof” before it can used in court.
This also goes into what surprised me the most; which was the idea that a lot of the physical evidence is not as reliable as I once thought. I was under the impression that ballistic along with handwriting analysis was very accurate this came from information I had gotten through watching shows like “forensic files” and other shows that are based off real investigations.
I would like to know more about expertise testimony or more specifically why these techniques can be used in the court rooms against a person if there are so many variables and people who can read the same information differently. I didn’t really find any information on why testimony is allowed into court cases even when they have been proven to be controversial. The only information is about the Daubert Standards.
Chapter four is about trace evidence and how it can be used in the court room. Not only does it talk about what evidence has been accepted in cases but it also discusses the different biases and how the court room is trying to remove them. There were many parts of this chapter that I found interesting, among them were the trace “match” a source, DNA, fingerprints, and techniques of weak or unknown validity. These really stuck out to me because when watching television series all of these methods are used and work almost always. The cases that were also brought up throughout this chapter struck my attention as well. The fact that not all crime scenes lead to the suspect is a very frustrating concept and is hopefully one that can be fixed in the near future.
I found that the most common forms of trace evidence are bloodstains, hair, textile, fibers, paint, and glass fragments. When showing up at a crime scene, each one of these sources is important to look for that way investigators know where to begin when searching for the suspect. Another helpful part in the investigation is rough surfaces because they hold trace evidence longer than smooth surfaces. The persistence of trace evidence, however, is a problem. This is because there can be discrepancies in findings as time passes by once a crime has been committed. I was also surprised about how much trace evidence can really be analyzed. Even though I listed the few at the beginning, while doing more research, the list seemed to expand. While looking through the last link, I couldn’t believe how much work went into trace evidence. Not only does it have to be found at the scene but it also has to go through many evaluations, involves a lot of statistics, and requires a lot of special care that way it doesn’t get tainted. These are just a few of the many things that I found informational to add to this chapter and to expand my knowledge as well.
http://www.enotes.com/forensic-science/trace-evidence : I found this website interesting because it gave more information on trace evidence and how it can be helpful in some cases and is hard to discover in others.
http://books.google.com/books?id=K7s8PYcus5IC&pg=PA140&lpg=PA140&dq=persistence+a+problem+in+trace+evidence&source=bl&ots=tjU4-M3LHQ&sig=Ulmw0a79mLoKjXN1jW7UNSzAtug&hl=en&ei=_X9_TvR-xeSxAoTmrAg&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CB4Q6AEwAA#v=onepage&q=persistence%20a%20problem%20in%20trace%20evidence&f=false : I liked this source because it talked about the persistence of trace evidence and even showed how much statistics is involved.
1. I thought it was interesting to see how poor trace evidence was to a case. It was odd because you see in TV shows and movies that the DNA and fingerprints are the major players to a case but as shown in this chapter we saw that that's not true, they can be mixed up and no reliable.
2. I think it was surprising how government agencies have been been wrong like in the case of Brandon Mayfield and yet the FBI would not listen and almost convicted the wrong person in the case.
3. Trace evidence does however help investigators know where to start like if a window is broke when is it broken, was it broken in or out of, this all is a good way to get the investigation underway and can help piece together a story as soon can they can.
http://www.enotes.com/forensic-science/trace-evidence
1. I thought it was interesting to see how poor trace evidence was to a case. It was odd because you see in TV shows and movies that the DNA and fingerprints are the major players to a case but as shown in this chapter we saw that that's not true, they can be mixed up and no reliable.
2. I think it was surprising how government agencies have been been wrong like in the case of Brandon Mayfield and yet the FBI would not listen and almost convicted the wrong person in the case.
3. Trace evidence does however help investigators know where to start like if a window is broke when is it broken, was it broken in or out of, this all is a good way to get the investigation underway and can help piece together a story as soon can they can.
http://www.enotes.com/forensic-science/trace-evidence
**My book just arrived**
The story in the beginning really caught me. I was astounded at the confirmation bias especially since the fingerprints are easily identifiable as different. Fingerprint a has a hoop in it in the middle upper left that isn't present on fingerprint b and that is clearly identifiable in c. Granted, while that does not mean that a=c, it does rule out b.
I found it really interesting both how specific the language is, but how questionable it's accuracy. They've tried to increase the accuracy by codifying responses but even so it is approximated based on partial statistics. There's always a danger in qualitative scales for information but in this case it seems the best that could be done. Even to expand the scale would only serve to make the distinctions even more grey.
Random Match Probabilities struck me as particularly prudent to study, and to learn more about. When levered against how evidence can degrade resulting in only partial matches, it gets really interesting if extraordinarily technical.
http://www.bioforensics.com/conference/RMP/index.html
http://www.bioforensics.com/conference/RMP/RMP%20-%20irrelevant.pdf
Chapter four discussed the aspects of forensic identification such as DNA, Fingerprints, and Trace Physical Evidence. These are all things that may or may not be left at a crime scene. In many cases these can be the only things we have for evidence. The problem seems to be that these are really not that good for being evidence. If you look at this type of ‘evidence’ you must take in account the reliability and validity of them. There also must be a check for biases and error, which can occur very easily and frequently. Nowadays more advanced technology is overpowering the ‘old’ ways of identification.
The most interesting thing I learned was the use of the examiners in the case. This would clearly cause bias for the examiner to convict the person they believed did the crime. There needs to be a way to have cross examinations and completely different people on cases. There could also be more use of double blind studies to wipe out the biases. It just didn’t seem right to me.
What shocked me the most and what I wanted to look into more was the problems associated with false fingerprint analysis. You would think that you could pin the correct person to the crime with the real fingerprints, but funny stuff can happen. When I looked into it more, it seems as though this was a major problem for the wrongfully accused! Many people are put in jail every year, because there isn’t really any evidence besides fingerprints and they get pinned on the wrong person. I think this is caused by cops not having proper training. I know a lot of dumb cops and it’s not right that that person can determine my fate!
http://www.criminal-law-lawyer-source.com/articles/fingerprint-error-false-arrest.html
http://www.msnbc.msn.com/id/27233798/ns/us_news-crime_and_courts/t/review-lapd-fingerprint-unit-sought/
This chapter was about DNA, fingerprints, and physical trace evidence. Trace evidence is any sort of evidence that can be connected back to the crime scene. I learned that there are a lot of different technical terms for deciding the reliability in connection between trace evidence and its comparison sample. Source attribution being they just come from a common source, inclusion being so substantially similar they are a match, and individuation saying that the trace found at the crime could only come from a certain source in the world. I had no clue that the classifications were more complicated than match or not.
I also learned that fingerprinting is a fairly unreliable source of trace evidence. They say that no two snowflakes are alike, but some are so similar you can't tell the physical difference. Due to the number of people in the world, it's argued that fingerprints are the same. Law enforcement is more concerned with the chances that it came from someone else though, as opposed to whether or not there's an identical one somewhere in the world. Also, during the identification procedure, a ridgeologist looks at the trace print and compares it to the sample print. According to the one dissimilarity doctrine, if there is a single unexplained dissimilarity then no identification will be made. Well this brings me to why fingerprinting is so unreliable, bias. Often times, the ridgeologist knows about the case, and isn't detached from it. This surprised me, having an outside person do this would seem much more reliable to me. But when a ridgeologist thinks they know who the perpetrator is, they'll go to extra lengths to find an explanation for the dissimilarity. It's not uncommon for a print to be read wrong because of this reason.
I learned that DNA is currently the most reliable form of trace evidence, and it works differently than I had thought it did. I always assumed that when DNA was looked at, you compared them, and if they matched you had your perp. Well it's more based on a statistical representation than it is that. When people look at DNA, they are looking for the probability that the trace evidence could only belong to that person. So if There were five people, theoretically, with very similar DNA, and one sample matched just a tad bit more than the others in more areas, they have a higher probability of it being their DNA, but it's not necessarily conclusive. DNA can be damaged depending on a lot of factors. Even still though, DNA seems to be much more reliable than fingerprinting.
One thing that surprised me most, is how little weight jurors put on statistical models of probability as evidence. At first it really surprised me, but then it made sense. Statistics are confusing, and those statistics being presented in their raw form would make little sense to most jurors. It would help a lot, and the evidence would be weighed far greater, if the information was simplified.
http://www.fingerprinting.com/fingerprinting-products.php I was interested in seeing on this page how many different fingerprint products there were. Not only are there the fingerprint kits for law enforcement, but there are fingerprint kids for kids in case they are abducted! They have it on safes so that only you can open it, they have it on time clocks to eradicate the need to have time clock cards, and they even have jewelry popping up now with fingerprints being the artistic part of it! I never realized how many uses fingerprints had!
I learned that there are a lot of different terms for classifying different types of trace evidence. source attribution is the term for when trace evidence and a sample come from a common source, inclusion is when the two samples are very similar and have no unexplainable differences, and individuation is the term used for when the the trace evidence could only come from a certain source anywhere in the world. If there are inconsistent features between the samples the suspect is excluded as the source. And finally, if trace evidence is contaminated, the comparison is inconclusive. I had no idea that there were so many different terms for finding a match!
I learned that fingerprinting is a much less reliable form of evidence than I have grown up being told. Not only is there not a record of every single person's fingerprint in the world, but there is a lot of bias involved when it comes to identifying a fingerprint. A ridgeologist is the one that identifies fingerprints. They look at the prints and see if there are enough similarities that lack and unexplainable dissimilarity. The one dissimilarity doctrine is the idea that if there is one unexplained dissimilarity, then there is no match. But because of bias, many professionals will find someway to explain the dissimilarity. Bias plays a huge role, and an even bigger one the more a ridgeologist knows about the case. If someone comes into the identifying part of this already convinced that someone committed a crime, they may find a way to justify that a dissimilar print is the same as the suspect. It would be more practical to have someone who knows nothing about the case look at this than how we do it now, being the professionals know details about the case beforehand.
I also learned that there are even less reliable means of evidence than the above. Comparing bullets, for example. An analyst looks at the markings on the two bullets and decide if there is a significant similarity between the two. This theoretically allows one to decide if the gun that a suspect owns is the one that was used to shoot a victim. Well, there is no standard about how many markings or striations should be apparent in certain types of bullets or guns, so it all comes down to the analysts personal beliefs in deciding whether they are the same or different. Even things such as teeth markings or tool markings at the scene, which have little empirical evidence supporting their use, is used sometimes as evidence. Techniques like these should be viewed with a grain of salt.
The thing that surprised me most was how little jurors weight statistical evidence. but after thinking about it, it made sense. Statistical evidence can be very confusing, and when presented in its raw form, very few jurors would be able to comprehend what they are seeing. To them it's just a jumble of numbers, and something you can't understand isn't seemingly very reliable. So in order to make statistical evidence more beneficial, the statistics need to be explained in a way that a person could better understand. This would help jurors make better use of the evidence at hand.
http://www.fingerprinting.com/fingerprinting-products.php I was surprised to find on this page all the different types of fingerprint merchandise you can get. It's not just fingerprint kits for law enforcement. You got fingerprint readers on safes to make sure you're the only one that can get in them, you got time clocks with fingerprint identification to eliminate the use of time clock cards, and there are even types of jewelry coming out that have fingerprints as their artistic center! I never knew fingerprints could be used for so many things!