Generality of the complementarity pattern across online markets

Determine whether the complementarity pattern between seller reputation and third-party certification identified in the eBay Pokémon trading-card market also holds in markets with different cost structures, including the eBay Motors used-car market where voluntary seller disclosure operates without a comparable third-party grading service.

Background

The paper develops and tests a signaling model in which reputation deters dishonest self-grading through an ex-post reputational penalty, whereas third-party certification establishes credibility through an ex-ante monetary cost. In the empirical analysis of nearly one million US eBay Pokémon-card listings, these mechanisms occupy different regions of the reputation–value space and jointly extend credible exchange across market conditions.

The authors caution that the empirical setting is a single collectibles market with mature third-party grading infrastructure. They explicitly leave unresolved whether the same complementarity pattern generalizes to markets in which the relative costs and availability of reputation, disclosure, and institutional certification differ, identifying the eBay Motors used-car market as a concrete comparison.