We study a nonlinear two-way fixed effects panel model that allows for unobserved individual heterogeneity in slopes (interacting with covariates) and (unknown) flexibly specified link function. The former is particularly relevant when the researcher is interested in the distributional causal...

According to the Hicksian criterion, two products are complements if their (compensated) cross-price elasticity is negative. While attractive in theory, the implementation of the Hicksian criterion can be hard: computing elasticities requires the estimation of structural models allowing for both...