I'm an Assistant Professor of Economics at the School of Business and Economics of Universidad de los Andes, Chile.
My research focuses on the intersection between industrial organization and health economics.
Email: wxiong@uandes.cl | Link to my CV
Abstract. This paper studies how selection outcomes in an individual insurance market shape the hospital market. In a setting with horizontally and vertically differentiated hospitals, consumers who prefer high-quality but expensive 'star' hospitals are costlier to insure. Competitive multi-plan insurers respond by offering tiered- and narrow-network plans to attract consumers less likely to use expensive providers. However, enrollment in these plans reduces the average coverage that insurers assume at star hospitals and weakens insurers' bargaining incentives, creating a feedback loop that elevates star hospital prices and enlarges the premium differences between network policies. Using industry-wide claims and enrollment data from Chile, I estimate that insurers' tiered provider networks explain 18% of the observed three-fold price ratio between high- and low-cost hospitals. Eliminating network choices mitigates both adverse and advantageous selection on hospital preferences, shifts patients toward star hospitals, and reduces profitability disparities across providers.
Survival and Selection under Incomplete Insurance: Evidence from Chile’s Mixed Public-Private Health System
with Dominique Araya
Status: Draft coming soon
Abstract. This paper investigates the mortality effects of private hospital use among government-insured patients. We develop and estimate a marginal treatment effect framework for a binary outcome that allows for both selection heterogeneity and treatment effect heterogeneity. Using eight years of nationwide hospital discharge data from Chile and a continuous instrumental variable derived from variation in public voucher subsidies, we find large heterogeneity in treatment effects: for some patients, private hospital admission increases survival probabilities by up to 10-15 percentage points. Patient self-selection is shaped by two opposing forces: while Roy sorting drives patients with high potential survival gains toward private hospitals, financial risk deters them from doing so. Because private hospitals hold a capacity advantage in intensive care, comparing self-selection with centralized transfers highlights the potential of relaxing financial barriers to enable positive Roy sorting to realize the survival advantage of private care.
The Waiting and Matching Quality Trade-off in Kidney Transplants
Summary. This paper leverages a particular policy in Chile that permits private hospitals that procure deceased donor organs from remote areas to retain one of the two kidneys they receive, prioritizing their own patients. As a result, patients in need of kidney transplantation face different waiting times and matching quality between public and private hospitals: the national list has a longer wait time but better matching quality due to a greater market "thickness" for available kidneys and transplant candidates, whereas the private hospital list has a shorter wait time but lower matching quality. I quantify the tradeoff by comparing the life-years from transplantation between the two sectors, using distance to dialysis centers as an instrumental variable for the binary choice between dialysis and transplantation.
Pricing Water under Scarcity and Adverse Selection: Theory and Evidence
with Juan-Pablo Montero
Summary. We confirm an emerging empirical observation that utility consumers respond to average price rather than marginal price. Given the average price bias, we derive optimal block price schedules under water scarcity. We estimate the key parameters using detailed administrative data that spans ten years and covers every household in the Metropolitan region of Santiago, Chile.
