​Resumo WP n.º 27:
This article estimates the price elasticities of the demand for mobile telephone calls and the demand for messages for Portugal. We use a panel of individual level data. In order to account for the unobserved individual heterogeneity and for the data censoring, we estimate a Tobit model for panel data with individual random effects. The demand for calls and the demand for messages are inelastic. Calls and messages are complements.