I apologise for mixing you up with the OP, I realised what I had done after hiding the thread.
So to go back to what you said about teenagers lying - I have just had a look at Nancy Darling's research and have found a couple of other sources which I think are more helpful way of presenting the same research, compared to giving a bare percentage:
Dr. Shefali Tsabary: "There is only one reason a child lies to its parents: the conditions for it to feel safe have not been created."
Dr Laura Markham (clinical psychologist with expertise around child development): "[This is what the research says about lying.] Many, if not most, kids lie. However, kids whose parents don't punish and who feel they can talk with their parents about their challenges generally do not lie to their parents. They have no reason to. Is is possible to raise kids without punishment? Absolutely. They turn out a whole lot better, in every way, because they become self-disciplined, once they aren't being disciplined from outside." [she gives a lot of other helpful and constructive advice on her website and there are some youtube videos in case anyone is interested]
So as you see the above draw on the same research as Nancy Darling, but the advice given is presented differently, that is, they give a different emphasis when presenting their advice.
To some extent the same thing is going to apply to school - if teens and tweens who would normally lie are put into a school environment where they feel safe, the likelihood of lying will diminish.
The bare percentage which jumps out at you from Nancy Darling is going to encourage adults who are not entirely scrupulous to manipulate when they are wanting to get away with abuse towards teens or tweens, unfortunately, so that is a shame. Although if teachers had training in child development research as standard, they might be able to distinguish.