this is a hard to define and hard to measure quality that i would propose represents how much a person "doesn't let her/himself off the hook" about tough ethical questions, and how everyday choices are really often ethical decisions

from personal experience, there may be some topics on which an individual has a high degree of integrity, while with respect to other areas of that person's life there may have been choices made which represent a lower degree of integrity  -- my hunch is that the correct analysis will not want to distill these things  down to a single value for a single individual (with the exceptional case being the person who's completely internally consistent in facet of her/his life)  --  it's the specifics of exactly where the individual has drawn boundaries in the past (and which of those boundaries are subject to possible modification) that really matters when evaluating whether or not an individual is trustworthy