alt Hacker Newsmost people are embarrassed about the truth. So they will over report vegetables while not mentioning how much alcohol or tobacco they had (or illegal drugs which the study probably legally must report to the police). Or a self proclaimed vegetarian will not report meat they ate despite their claim. fat people will report they skipped desert.
Replies
graemep • 01/21/2025
I came across a comment as a humorous rule of thumb for this.
1. If you ask someone who much the drink double the answer 2. If you ask them how much the smoke, multiply the answer by five 3. If you ask them how often they have sex, divide the answer by 10.
Why would that be a problem for reporting relative results if the entire population is doing that?
If everyone is under-reporting their alcohol consumption, that seems fine. The absolute numbers will be way off, the relative numbers to their peers won't.