Dmitry A. Shapiro’s research while affiliated with Seoul National University and other places

We study how the inaccuracy of a costly certification technology affects a monopolistic seller's profitability. We compare three scenarios: no certification, a 100% accurate certification, and a 50% accurate certification that produces accurate evaluations half the time. The noisy certification environment is never the most profitable and, depending on the buyers' loss aversion, can be the least profitable. However, a noisy certification can be more profitable than an accurate one, as it discourages the over‐certification that occurs in an accurate certification environment. Experimentally, the noisy certification is shown to be the least profitable treatment, whereas the accurate certification is shown to be the most profitable.

We provide a theoretical and empirical analysis of strategic momentum and psychological momentum in best-of-three contests between players with unequal skills. As a theoretical benchmark, we develop a fully rational model of best-of-three contests and define psychological momentum as systematic deviation from the theoretical equilibrium. An empirical analysis of 66,262 professional tennis matches from 2002 to 2020 shows that our theoretical model closely matches first set outcomes, which is when set-level psychological momentum is absent. Overall, the empirical results show that both strategic momentum and psychological momentum contribute to the outcomes of best-of-three tennis contests.

We provide a theoretical and empirical analysis of set-level strategic and psychological momentums in a sample of 8,193 ATP best-of-five-set tennis matches where players have asymmetric abilities. Theoretical predictions match observed Set 1 outcomes, the only set with no set-level psychological momentum, but do not match any other sets. We find evidence of psychological reversal: in every set following a non-tie net score, the winner of the previous set underperforms compared to theoretical predictions.

The comparative ignorance hypothesis, first demonstrated in Heath and Tversky (1991), is that ambiguity aversion is driven by the comparison with more familiar events or more knowledgeable individuals. For example, when own ignorance is perceived to be higher, individuals tend to exhibit stronger ambiguity aversion. We use this insight to provide a theoretical explanation to a well-documented phenomenon of business training having limited, or even negative, effect on post-training profits of program participants.

The paper studies incentives of low‐quality sellers to disclose negative information about their products. We develop a model in which one's quality can be communicated via cheap‐talk messages only. This setting limits the ability of high‐quality sellers to separate, as any communication strategy they pursue can be costlessly imitated by low‐quality sellers. We study two factors that can incentivize low‐quality sellers to communicate their quality: buyers' loss aversion and competition. Quality disclosure reduces buyers' risk, thereby increasing their willingness to pay for the product. It also introduces product differentiation, softening the competition.