Specific details about how the data collection and processing was done. For example in my field there were a lot of fussy details that if they were not handled correctly (and most people did not handle them correctly) would lead to false positives/false negatives.
If something is outside my area of expertise, then I have limited ability to judge a paper based on its methods.
If something is outside my area of expertise, then I have limited ability to judge a paper based on its methods.