Picking 1,980 people from 100,000 and get 990 out of 1,000 who have DSX is in fact quite impressive--99% recall (in information retrieval) or sensitivity (in me

Picking 1,980 people from 100,000 and get 990 out of 1,000 who have DSX is in fact quite impressive--99% recall (in information retrieval) or sensitivity (in medicine). In information retrieval, you rarely get that sort of number out of unstructured data. If you look at the predicted positives for rare conditions (as in your DSX example), you may find that 50% are false positives. It is still considered useful for many purposes. In medicine, for example, it is used as a first-round filter to screen people for another, more expensive/cumbersome test.