How do you check if research about Islam is credible?

How not to get duped by sloppy Western academic 'scholarship' in Islamic studies: Do not get impressed by diacritical marks and extensive footnotes. You may laugh, but the subconscious effect is there if you are not wary enough. If it is important to the case the academic is building, make sure to verify the source. You would be amazed at how many and the kinds of errors and misquotations you would discover. If the source does check out, then research the author's overall stance by seeing everything else he said on the topic to ensure that the academic is not cherry-picking his statements. Have access to a senior student of knowledge of the discipline you are reading in that is not influenced by the epistemological standards of the Western academy. By "access" I mean someone who will give you the time of day and has the patience and interest to help you out with your queries. Pay careful attention to faulty deductions and non-sequiturs. There are Western academics that do not make careless factual errors. Their research is mainly factually accurate however contentious deductions at the heart of their case are relayed in a few sentences that can easily elude your radar (often seen in concluding remarks). Traditional Muslim authors make mistakes too, absolutely. But the difference is that they operate within acceptable legitimate boundaries (unless pointed out otherwise) and tend to not argue for something radically unacceptable due to their adherence to commonly shared methods of research and inquiry.