Can users estimate their usage of a web-based application? Validating a self-report usage questionnaire.

User surveys are often used to estimate usage of online systems. We asked medical student to estimate their weekly use of KnowledgeMap, an online medical education system, during the previous semester. The information was validated against server log files. The average number of log-on days was significantly different across four categories of self-reported use. Self-reported frequency scales may be used to correctly segregate users into discrete ordinal usage groups.