About Me

I am an Economist working in the fields of Matching and Digital Platforms. Currently, I am an Assistant Professor in the Strategy Group from the School of Management at the Pontificia Universidad Católica de Chile.

Education

Ph.D. in Economics, University of Maryland at College Park, May 2019
M.S. in Economics, Getulio Vargas Foundation Graduate School of Economics, 2013
B.A. in Economics, Federal University of Ceará, 2010 (Magna cum Laude)

Positions

2019-Present: Assistant professor at the School of Management at Pontificia Universidad Católica de Chile
2013: Part time instructor at the department of Statistics and Applied Math at the Federal University of Ceará

Published Papers

An Upper Bound to the Benefits of Implementing Positive Assortative Matching in Pooled Testing (2026) Health Care Management Science

Dorfman pooled testing combines individual specimens (e.g., blood samples) into one test; if the pooled sample tests positive for infection, each specimen is tested separately. Under small prevalence levels, this method is known to reduce the expected number of tests required to screen a population, as individual tests only occur when a pooled test detects an infection. When conducting Dorfman testing, studies often recommend implementing positive assortative matching, i.e., pooling together samples with a similar risk of infection, as this tends to minimize the expected number of tests, the expected number of false negatives, and the expected number of false positives. However, because the logistics of collecting data and assorting samples from lowest to highest probability of infection can be costly, one may ask if implementing this procedure is indeed cost-effective. This article provides easy-to-compute upper bounds to the benefits of implementing Dorfman testing with positive assortative matching instead of matching samples randomly. Testers can then compare these upper bounds with the costs of estimating the probabilities of infection from each sample and then matching together those with similar risk of infection, to aid their decision on whether or not to implement this method.

Search Steering in Two-Sided Platforms (2024) (with Pedro Guinsburg), ACM Transactions on Economics and Computation

Many two-sided platforms are known to steer customers towards certain products based on their willingness to pay. In this article, we study platforms' incentives to adopt this type of market segmentation and present conditions under which this can generate distortions that negatively impact the surplus from buyers and sellers. In our environment, a monopolistic platform matches sellers with buyers. Upon being matched, each pair of buyer and seller negotiates prices. If they choose to transact, the platform receives a commission fee proportional to the value of the transaction plus a flat fee per transaction. The platform is assumed to have full information about customers' and sellers' outside options. We show that, as long as the market is in excess supply or as long as there is a crossing between the demand and supply curves, the platform's optimal matching is suboptimal from the perspective of buyers and sellers.

Strategic Incentives when Implementing Dorfman Testing with Assortative Matching (2023), Economics Letters

The Dorfman pooled testing scheme is a process in which individual specimens (e.g., blood, urine, swabs, etc.) are pooled and tested together; if the merged sample tests positive for infection, each specimen from the pool is tested individually. Through this procedure, laboratories can reduce the expected number of tests required to screen a population. The literature has often advocated in favor of using ordered partitions to screen the population, i.e., of pooling subjects with similar probability of infection together, as doing so simultaneously minimizes the expected number of tests, the expected number of false negatives, and the expected number of false positive classifications, provided that certain technical conditions hold. One potential limitation of using ordered partitions, however, is that they may incentivize some subjects to misreport their types to the tester. Indeed, if subjects wish to avoid being detected as infected, ordered partitions would incentivize them to falsely claim that they have a low probability of infection (assuming that pooled testing is subject to dilution effects). These incentives would disappear if subjects were matched randomly, regardless of their probability of infection. In this article, we derive conditions under which ordered partitions outperform matching subjects randomly, despite these incentives.

Pool Testing with Dilution Effects and Heterogeneous Priors (2023), Health Care Management Science

The Dorfman pooled testing scheme is a process in which individual specimens (e.g., blood, urine, swabs, etc.) are pooled and tested together; if the merged sample tests positive for infection, then each specimen from the pool is tested individually. Through this procedure, laboratories can reduce the expected number of tests required to screen the population, as individual tests are only carried out when the pooled test detects infection. Several different partitions of the population can be used to form the pools. In this study we analyze the performance of ordered partitions, those in which subjects with similar probability of infection are pooled together. We derive sufficient conditions under which ordered partitions outperform other types of partitions in terms of minimizing the expected number of tests, the expected number of false negatives, and the expected number of false positive classifications. These sufficient conditions can be easily verified in practical applications, once the dilution effect has been estimated. We also propose a measure of equity and present conditions under which this measure is maximized by ordered partitions.

An Improved Bound to Manipulation in Large Stable Matches (2021), Games and Economic Behavior

This paper builds on Kojima and Pathak (2009)'s result of vanishing manipulability in large stable mechanisms. We show that convergence toward truth-telling in stable mechanisms can be achieved much faster if colleges' preferences are independently drawn from an uniform distribution. Another novelty from our results is that they can be applied to competitive environments in which virtually all vacancies end up being filled. So this paper adds evidence to the fact that, though stable matching mechanisms are not entirely strategy-proof, in practice, when the number of participants in the market is sufficiently large, they can be treated as being effectively strategy-proof.

Working Papers

Awards

FONDECYT Iniciacíon Científica, 2023
eBay Research Policy Scholarship, Fall 2018

Apps

Pooled testing
This free online interactive tool can be used to assess the benefits of implementing Pooled testing (Dorfman testing) compared to matching samples individually. It also computes the benefits and maximum achievable benefits of matching together those with similar probabilities of infection when implementing Dorfman testing. The app also computes the optimal pool configuration when pool sizes are allowed to be heterogeneous and probabilities of infection are heterogeneous. For all of these features, the app allows users to calibrate the dilution effect and costs associated with classification errors.

If you would like to share your feedback on any of these apps, please send me an email :)

Gustavo Quinderé Saraiva