The complementarity between calls and messages in mobile telephony
Résumé
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.