What the poster above meant is that if you do a meta-analysis on already published results you could already know if it's a null result or not. If you are incli

What the poster above meant is that if you do a meta-analysis on already published results you could already know if it's a null result or not. If you are inclined to not publish null results, you simply won't "preregister". Of course to be a proper study they should pre-register and only report on future publications.