- Check that the source cited actually exists
- Check that the source cited backs up the part of the sentence that really needs backing up.
- Check that the source cited actually backs up the thing it's being used to back up, and doesn't just reference it obliquely.
- Check that the source cited states the point as strongly as the article authors state it.
- Check that the reference isn't so old as to be outdated, replaced, or from a paper that has been unreplicatable.
- Check that the reference was from an actual journal and/or otherwise reflects real scientific inquiry
I add this one on because the word "study" and "survey" get tossed around rather loosely at times. Two examples that made me think of this:
First, from England:
Mr Gove said: “Survey after survey has revealed disturbing historical ignorance, with one teenager in five believing Winston Churchill was a fictional character while 58 per cent think Sherlock Holmes was real."
Those surveys, the Department has now revealed in response to an FOI request, included research conducted by Premier Inn, the budget hotel chain, UKTV Gold and “an article by London Mums Magazine”. None are known for their work in this field.
Mr Gove is apparently the British equivalent of the Secretary of Education.
Second was from a website with a rather interesting name (Manboobz). The owner was apparently reading a book in which he saw the claim that schoolgirls hit schoolboys 20 times more often than schoolboys hit schoolgirls. Upon investigating that citation, he discovered that it was not actually a formal study, but a class project a friend of his had assigned her students at his request.
These may both be small things, and the points they make may or may not be valid...but when in doubt it's always worth checking the source of the source. The answers could be surprising.