In History at school we learnt the PANDA method to analyse sources, to test for bias and authenticity.
Purpose - What is the purpose for which the source was created? Was it to convert people to a specific way of thinking?
Author - What background is the author from? Could there be possible bias from the authors viewpoint as a result of their circumstances?
Nature - What form is the source in? (e.g. poster, map, photo, etc)
Date - When was it produced? Is it primary or secondary?
Audience - Who is the intended audience? (e.g. Aryans/Jews/male/female/etc)?
What are the advantages/shortcomings of this method as a quick & dirty guideline for analysis of sources?