How do you assess the validity of a historical source?

A good acronym to remember when assessing sources is DAMIT. D = Date: When was the source produced? Did any major historical events take place around this date? Is the source typical of the time? How long after the event was this source produced? Does the author have hindsight?A = Author & Audience: Who produced this source? What is the background of the person who produced this source? - i.e. were they educated? Is the source primary or secondary? - Was the individual there? Who was the source produced for?M = Motive: Why was this source produced? - i.e. to inform or entertain? Could these motives effect how reliable the source is? - i.e. is it biased? I = Information: What information is included in the source? - Why? Is there any information missing from the source? - Could you suggest why? What type of source is it? - i.e. Church records - are they typical of this type of document? Would there be any reason to believe the information had been tampered with? Is the information included supported by evidence?T = Tone: Is the source positive or negative? Does its' tone match this? Is the tone of the source typical, given its' author? Does the tone of the source give reason to raise concerns surrounding it?