Rafael Matta

Optimal Product Placement

We model a market, such as an online software market, in which an intermediary connects sellers and buyers by displaying sellers’ products. With two vertically-differentiated products, an intermediary can place either: (1) one product, not necessarily the better one, on the first page, and the other hidden on the second page; or (2) both products on the first page. We show that it can be optimal for the intermediary to obfuscate a product—possibly the better one—since this weakens price competition and allows the sellers to extract a greater surplus from buyers; however, it is not socially optimal. The choice of which one to obfuscate depends on the distribution of search costs.

Optimal Front Page Advertising

We consider a model of an on-line software market, where an intermediary distributes products from sellers to buyers. When products of sellers are vertically differentiated, an intermediary, earning a proportion of sales, has an incentive to hide the worse product on the second page, and only keep the better product on the front page: that weakens the competition, allowing the seller with the better product to charge a higher price. With heterogeneous visiting costs to the second page, the platform’s revenue might improve, but the outcome will become socially suboptimal.

The Effect of Age at School Entry on College Admission: A Regression-Discontinuity Approach

The consequences of single-date school entry systems, which generate a large age difference between kids in the same class, are now a widely studied subject. Published research has shown that older kids consistently outperform their younger counterparts in several outcomes while in elementary and in the beginning of high school, however, evidences are weak when one considers long-run outcomes such as wages or the probability of being employed. In this paper we use data from a major university in Brazil to investigate whether age differences significantly affect students’ college entrance test scores and their probability of being accepted for higher education. Our results show that older students outperform younger students on test scores and, more importantly, this difference significantly affects their likelihood of being accepted in college. These results suggest that age differences might have important long-run effects given its direct link to students’ access to higher education.This paper provides evidence of the effect of age at school entry on college admission. We do so by exploiting a number of features in the application process to one of the major flagship universities in Brazil. By comparing applicants with different ages at school entry depending on whether they are born on December 31st or on January 1st, our estimates show that delaying first-grade enrollment by one year increases the aptitude test score and the probability of admission. Our results further suggest that the difference in the likelihood of admission is driven by candidates’ learning ability at primary school, rather than by their knowledge accumulated prior to school entry or their maturity on the date of the admission exam. Finally, advantaged applicants also receive higher earnings early in their careers.