ATTRITION BIAS IN THE CAPITALIA PANEL

The Capitalia survey of manufacturing firms in Italy represents an important source of panel data on Italian firms. Panel attrition, however, represents a potential obstacle to such use of the sample. In this paper, sample entry and exit behaviour are studied, and a test for attrition bias is carried out in order to evaluate the potential for using panels constructed from the Capitalia survey. The analysis reveals the presence of distorting panel attrition effects in simple models of firm performance. In addition, the paper discusses both the implications of attrition bias for estimates and also briefly considers possible solutions. Finally, some suggestions are made as to how to reduce the impact of attrition bias through the provision of additional information on the nature of the attrition process available to the surveying institution at the moment of data collection