[Fred]

Questions:

Why do people reference population reports?

1) determine scarcity
2) see who has the best graded item (assume cards)

If it's to determine scarcity then you need to ask yourself, just how accurate are the pop reports. First, we all know subjectivity for TPGs is notoriously crappy. So, just because the pop report indicates X number of "8" grades, you ask yourself, could there be "6's" or "7's" in there? Then, what about all the cross-overs. The crossed-over cards are not removed from another TPGs database so the aggregate count on a specific card for a certain grade may be overstated when considering all TPGs accounting.

What about cards that people just didn't bother grading because how many people really want an Evans T206? Using T206 as an example, how well did the TPGs document the backs? For N172, the TPGs initially didn't include the pose number and now only SGC does (that I'm aware of). What's sad is CSG doesn't reference by pose number and that's sad because they actually had a chance to be the only TPG that had accurate counts on quantities of pose numbers (I'll just stop there for N172 because there could be other variations accounted for).

For those that are doing a registry, they usually stick to a certain TPG (i.e., PSA or SGC). Their motivation is finding out who has the highest graded registry set. They probably contribute to inaccuracy of overall population because those registry collectors will cross-over and add to the inaccuracy of the overall population of the cards in existence.

Also, if I were a TPG and my overall quantities graded paled in comparison to the competition, why would I want to make that public because it could bias people to perhaps get their cards graded by the company that has actually handled the most and probably has a greater number of collectors dedicated to their registry collections.


Edited to add: And what about all the grading mistakes and mislabels. Sure those would be considered the exception, not the rule, however, we've all seen it.