Thanks for posting the link to your book--it's interesting reading.
There seems to be a fairly common error within:
> One 1992 telephone survey estimated that American civilians use guns in self-defense up to 2.5 million times every year – that is, about 1% of American adults have defended themselves with firearms.
We cannot simply divide the event count by the population count, because a single person may have used a gun more than once in a year. In fact, someone who has used a gun during the year is more likely to use one later in the year than someone who has not yet used one, because some people live in dangerous areas, are themselves belligerent, or both.
Seconded. A great book (I've read 75% of it so far).
About the error you mention - I think you are right - but the author brings up the ~1% because he is talking about 'base rate fallacy' - he wants to say that the errors from the 99% of the population will swamp the true signal from the 1%. So his ~1% number is likely qualitatively ok for what he is using it for. It should still be reworded though - one wants 0 errors in a book about statistics mistakes :)
This came up during editing for the book. I tried to settle it by checking the original survey, which I thought would surely report the number of incidents reported by each respondent, but they make no mention of it. So I can't tell how many people are involved per year.
There seems to be a fairly common error within:
> One 1992 telephone survey estimated that American civilians use guns in self-defense up to 2.5 million times every year – that is, about 1% of American adults have defended themselves with firearms.
We cannot simply divide the event count by the population count, because a single person may have used a gun more than once in a year. In fact, someone who has used a gun during the year is more likely to use one later in the year than someone who has not yet used one, because some people live in dangerous areas, are themselves belligerent, or both.