I've been following the discussion regarding the 'quality' of evidence with interest. At the end of the day it is the users decision how to use the levels of assessment, if at all. However, Family Historian follows the GedCom Standard (much more closely than other Genealogy programs that I have used) and that definition states the levels of quality as follows - 0 =Unreliable evidence or estimated data 1 =Questionable reliability of evidence (interviews, census, oral genealogies, or potential for bias for example, an autobiography) 2 =Secondary evidence, data officially recorded sometime after event 3 =Direct and primary evidence used, or by dominance of the evidence You will see that the definition is not 'black and white' but requires a degree of judgement. At the end of the day, the quality of the source citation is a matter of probability. I cannot think of a historic document that can be considered as guaranteed 100% accurate. If you intend to share or publish your research then it makes sense to stick with the GedCom standard.