GregP
Major
I am a bit baffled by this question. Are you actually, genuinely unfamiliar with the books I was referring to? You never heard of Mediterranean AirWar, or Black Cross Red Star, or Pacific Air War etc.?
The books like MAW etc. just list whatever claims which are extant, by both sides, and then lists the losses by both sides - according to their own records. It's really pretty simple. The losses come from direct access to the records of all air forces in action in the given Theater.
I thought most of the regulars in these forums were familiar with these books and had been for years.
Familiar.
You said "not just claims."
These books (Shores, ect) are exactly "claims and losses" with some other vetting but, again, you have to ask the exact definition of a victory. If a downed plane was recovered and flew again, it STILL got shot down and that victory should count.
Shores et al are great resources but are not as good as USAAF Study 85 in which claims were matched with flight reports and squadron records, all looked at by experienced military personnel with an eye toward accuracy. Again, there is no real possibility of matching with all vetted enemy loss records because some Axis records were lost.
I'd say Shores is a pretty decent source, as good as we are likely to get. I doubt he is 100% correct, but is a very good effort to be considered. But is definitely claims-and-losses-based.