Abstract:

A major and well-known "tool of our trade" is the collection of information through observation. The major applications of observation as an information-collection method may be classified into the categories of the audit, coincidental recording devices, and a general classification, direct observation. In this study we evaluate data which are obtained by audits which are performed on both distributors and consumers. The evaluation is performed from the point of view of a user of research. When we compare audit data with actual data, we will find a data bias. In this study the sources of data bias which may occur when audit data are used are carefully investigated. Empirical data are used to pinpoint the effects of a nonresponse bias in audit data. An informal analysis shows that the non-response bias is correlated with the factor price.