Wow,
a rate of drop-out like that would certainly make me doubtful of the results of the study. It seems reasonably likely that people dropped-out in a fashion that would be weighted in one way or another.
a rate of drop-out like that would certainly make me doubtful of the results of the study. It seems reasonably likely that people dropped-out in a fashion that would be weighted in one way or another.
A reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3227332/
Sometimes, you have to trust the quality of the journal and biostatistician if you aren't able to read everything yourself.
I'm reminded of a study using the Nintendo Wii to help keep elderly people mobile. 90+% of them stopped playing immediately, within days, of the researchers leaving.
So you're saying it's logical that a lot of people dropped out? Seems reasonable.
But that doesn't mean that you wouldn't have the problem of the high drop-out rate implying the final people remaining are biased sample. When you are filtering a large number of people down to a small number, making sure that small number is representative of the large number is a hard problem.
Maybe there's no solution or no easy solution. Doesn't change the problem.
If that's the case, then the test should say this in the instructions... (It's a classic example of setting expectations, introducing objections up front..)
> This test may not feel exciting. Some questions could seem childish. Other questions could make people feel silly for marking the incorrect answer. These extremes are required for the study.