Though largely agreeing with Colin Thompson, I have no use at all for the GEDCOM "quality" measures - they conflate a whole series of assessments into a single "citation" measure. Firstly, one should be able to grade individual *sources*. Secondly, each citation (for one event) may cover a number of detail items (e.g. in a census return relationship to Head, age, birthplace, occupation), some of which are more trustworthy than others. As with risk assessments, a full picture has to take account of every level. In general we don't do genealogy assessment that way. It's almost always much more subjective, so why make a rod for our backs?