New nonparametric methods that identify and estimate counterfactuals for individuals, when each is characterized by a vector of unobserved characteristics, are developed and applied to estimate systems of individual consumer demand and welfare measures. The unobserved characteristics are allowed...

We analyse consumers' search and purchase decisions on an Internet platform. Using a rich dataset on all adverts posted and transactions made on a major French Internet platform (PriceMinister), we show evidence of substantial price dispersion among adverts for the same product. We also show...

We document considerable within-person (over time) variation in diet quality that is not fully explained by responses to fluctuations in the economic environment. We propose a two-selves model that provides a structural interpretation to this variation, in which food choices are a compromise...