I found this fascinating. Amongst other interpretations,
“[The Hawthorne effect is] an experimental effect in the direction expected but not for the reason expected; i.e., a significant positive effect that turns out to have no causal basis in the theoretical motivation for the intervention, but is apparently due to the effect on the participants of knowing themselves to be studied in connection with the outcomes measured.”
I’m often sceptical of surveys and the like (especially of the “X% of children surveyed said they carried a knife!” type) because I suspect that people lie to pollsters more than they like to admit. This now adds another type of study I will forever be suspicious of…
[Found in a comment on this WSJ ‘Business Technology’ blog post about a study showing that “someone using a larger monitor could save 2.5 hours a day”].