Comment by bjornsing

Thanks for the extensive answer.

> I don't think the idea of a zero null hypothesis is necessarily mathematically unsound. In cases like the difference in means, a zero null hypothesis is well-posed. However, I agree with you that there are better practices, like a null hypothesis incorporating a nonzero effect.

I don’t think a zero null hypothesis is mathematically unsound of course. But I think it is unsound to do one and then look at the effect size as a known quantity. It’s not a known quantity, it’s a point estimate with a lot of uncertainty. The real underlying correlation may well be a lot lower than the point estimate.

And of course it’s hard to get people in charge interested in better hypothesis testing. That testing will result in fewer conclusions being drawn / fewer papers being published. It’s just another symptom of the core issue: it’s quite convenient to be able to buy the conclusions you want with money.