I know that’s a tricky question, and may make you think of cream pouring on apple crumble, discussions about chemotherapy, or episodes of Octonauts depending on exactly what frame of mind you’re in and background you have.
Within a research setting, however, how do we decide when something has been researched so much and folk have repeatedly found no/minimal effect, that we should just give it up. It doesn’t work (enough). This is a key decision to be made, and relies on a mixture of elements.
Take cognitive bias modification – as blogged about by the quite brilliant mental elf – it’s an idea that if you encourage folk to frame ambiguous situations in a positive way, they’ll be less depressed. You know .. that glass isn’t half empty … Anyway – yet another study shows there’s no real benefit in this. So – when do you stop researching?
We looked at an analogy here, in considering equivalence and non-inferiority. Add to those ideas the cost of intervention, the cost of more research (both doing it, and the ‘cost’ of not studying other stuff), then you can get to the answer. Then you’d know exactly when enough is enough.