Afonso Rodrigues - Research

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Job Market Paper

I introduce a novel, scalable demand estimation method that accounts for consumers’ real purchasing behaviour. Textbook rational consumers consider every possible consumption bundle. This is unrealistic and computationally infeasible; practical applications target discrete choice for a few goods within a product category. This in turn is shown to underestimate price elasticities, producing excessive estimates of market power and understating passthroughs. My proposed approach conditions the outcome of consumers’ utility maximisation problem on the structure of their consideration set, yielding novel theoretical predictions. If the consideration set binds, joint purchases induce substitutes and complements onto the system; market concentration becomes welfare-increasing. With a Slutsky matrix approximated from joint-purchase frequencies, these predictions enable modelling under more realistic conditions. Using point-of-sale data from a Portuguese supermarket chain, I determine price elasticities for 20,000 goods across 500 product categories from a grocery store sample from 2020-23. The results match observed price volatility, profit margin surveys, as well as reports on shifting consumer tastes during the sample period. Markups average 11%, with peaks and troughs corresponding to COVID-related events.

Lisbon Meetings in Game Theory and Applications, June 2025 - Best Graduate Paper 🎉

Working papers

"Market Structure and Pass-throughs in Regional Retail Fuel Markets". September, 2025

I develop a cross-nested logit demand system to study how market structure shapes the pass-through of cost shocks in national retail fuel markets, given regional variation in station density. Every gas station is defined as the centroid of a nest: a market within a given radius of said station, to which it and its competitors belong. To mitigate endogenous location choice, parameters are identified within stable windows where the set of local competitors is fixed. I show via simulations that the proposed model can allow for stronger spatial propagation of local shocks than canonical logit models, at higher equilibrium markups. The framework enables counterfactuals on entry, exit, and ownership, that respect realistic geographic substitution.

"Endogenous Multi-Attribute Choice and Market Structure". September, 2025

This paper develops a linear demand framework to investigate endogenous attribute choice in multi-good, multi-attribute settings. The key assumption of the model is that the same factors/attributes which drive goods utility also drive competition in the goods market. When a single multi-product monopolist jointly maximises profits across its portfolio, three configurations can emerge: it may concentrate every desirable attribute in one flagship product; it may launch a vertically ranked line in which each variant offers the same mix of attributes at progressively lower intensities; or it may supply several identical products, each mirroring the others’ attribute levels. However, I prove that a multi-good monopolist never chooses attributes and attribute intensities which yield horizontal differentiation. Preliminary work on extending this approach to single-product oligopolistic firms is also discussed.

How does the entry of a generic variety onto an industry change competitive outcomes, when said industry is composed of firms of distinct sizes? Conventional wisdom in competition policy perceives generics primarily as purveyors of increased market competition and consumer welfare gains. I analyse this question and consider the merits of the prevailing view using a product differentiation model, simultaneously integrating the standard settings of Cournot oligopolistic and Chamberlinian monopolistic competition, facing a new challenge from a perfectly competitive generic variety. I find generics entry to have an ambiguous impact along most dimensions of interest to producers and consumers; significant asymmetric and interacting effects based on firm size heterogeneity; consumer welfare opacity from observable market outcomes; and multiple channels for utility effects, both negative and positive. These results have relevant regulatory implications, suggesting a movement from policies aimed at lowering fixed generics entry costs to more active and granular strategies engaging with the consumer preferences, firm types, and product interactions within each targeted industry.