Factors explaining differences in wine experts' ratings: The case of gender, credentials, occupation and peer effects

The aim of this article is to better understand why experts give different scores to the same wines in identical tasting environments. This research focuses on the personal characteristics of experts (or judges), such as their gender, industry credentials, and occupation within the wine industry, and examines how judges respond to their peers' characteristics. Using a dataset of 5,395 wines judged in the 2022 International Wine and Spirits Competition, we analyse 18,224 scores from different judges. We estimate a series of grade equations at the judge level to understand why a same wine received different scores from judges. A first model makes use of the panel structure of the dataset, incorporates wine fixed effects, and focuses on the personal characteristics of judges. A second model encompasses characteristics of the judging team, without the inclusion of wine fixed effects. At large, on-trade buyers give lower scores than off-trade buyers, as well as female judges compared to male ones. While credentials are not a very significant factor per se, they do have the potential to generate peer effects. Judges tend to be more generous in their assessments when they are assigned to a team with Master of Wine judges. Conversely, they are also consistently more severe when the number of female judges on the team increases. Estimation results converge across sub-datasets, with the exception of sparkling wines. Given the feminisation of the wine industry, in terms of producers, consumers, and experts, the severity of female judges could be beneficial in terms of social welfare.