15 -years- is a LONG time for a study. I'm not sure about the dropout rates, but it is a real statistical issue. I'm just not sure there's anything that can r

15 -years- is a LONG time for a study. I'm not sure about the dropout rates, but it is a real statistical issue. I'm just not sure there's anything that can reasonably be done about it. You'd have to have something like federally mandated participation / continued participation. That's also very unlikely to pass ethics boards. BTW, it would also be an issue if the subjects were compensated to the point that they differed from the actual population at large. Fundamentally having more respect for doing things right, the right way, over the /long/ term, including the STEM fields, would be a 'good thing' for any society, but particularly western ones (where often the bad/evil antagonist is based on science or a cold lack of emotions; but the protagonist is based mostly on emotion and feeling instead of logic).