Evidences from survey data and fiscal data: nonresponse and measurement errors in annual incomes

A (local) survey on income carried out in the city of Modena in 2002, with income reference year 2001, generated four categories of units: interviewees, refusals, noncontacts, and unused reserves . In this study, all units were matched with their corresponding records in the Ministry of Finance 2001 database and the 2001 Census database. Considering all four categories, participation increased by education level and activity status, while it decreased among low or high incomes. Considering interviewees only, over- and under-reporting, as well as measurement errors, were investigated by comparing the surveyed income with fiscal income. Age and level of income were the main covariates affecting the behaviours of taxpayers.