A public database, maintained by grading services like PSA, BGS, and CGC, listing how many copies of a given card or collectible have been graded at each grade level. The pop report is essential for understanding rarity at top grades.

A card may have been printed in millions but have a population of only 10 in PSA 10 — making the high-grade copy genuinely rare even if the card itself is common. Learn to read population reports.