This question came from a mathematics PhD student who is attending my mathematics education research seminar in which we read published papers on various mathematics education research topics. I'm not sure what he meant by "bad" or whether he even knows. I am assuming it might be the kind of paper that "slipped through" the reviewing process and got published. That is, there might be something not well formed in the research question, or there might be something wrong with the data collection or the analysis.