Purpose: Online data collection is gaining momentum throughout the market research business. At the same time internet users and their online information and booking behaviour are becoming more and more important for the travel and tourism industry. This paper aims to investigate this issue....

This paper investigates how to test and correct for nonresponse selection bias induced by missing income information when estimating wage functions. The novelty is to use the variation in interviewer-specific response rates as exclusion restriction within the framework of a sample selection...