Here is a good example of a media article that cites research findings. A good exercise is to find a media article (such as this), then locate the original research, and see how well (or not) the media article did at explaining the science.
http://www.washingtonpost.com/wp-dyn/content/article/2008/12/28/AR2008122801588.html
I think the virginity pledges have their ups and downs. One positive thing about abstinces rings and pledges is that it gives a girl more self-esteem to turn down peer pressure to sex from other students and friends. It allows them to stay pure till marriage, reducing their chances of unwanted pregnacies and any STI's. The downside to this is that once they do decide to give themselves away to that special someone they are more likely not to be well educated on sexuality and contraceptives etc. So i think for those who do take a virginity pledge should have to take a pledge class or abstince class that gives them enough background on the sexual matter.
Here is anouther news article done by CNN on virginity pledges.
http://www.cnn.com/2008/HEALTH/12/30/virginity.pledges/index.html