For most studies of any kind, the margin for error is around +/-3%. For example, a study covering the United States population using a sample size of 1000 will yield a margin of error of 3.1%.
So a study says that texting while driving increases your risk of a fatal crash by 23 times. That sounds like a lot! But hold the phone...the overall rate of traffic fatalities is about 10 per 100,000 people, or about 0.01%. Multiply that by 23, and you get 0.23%. A big change, right? But that 0.23% is still well within the margin for error of most any study.
I'm not saying that texting while driving isn't dangerous. I'm just saying it's a lot harder to prove a link than it would seem.
Still, people are wowed by big multipliers, and news writers love to tout dramatic statistics, whether the subject of the study is economics, medicine, or traffic safety. But if you understand statistics, you know that most of these studies don't really tell us much. It's no wonder we keep getting contradictory study results!