The quality of questionnaire based software maintenance studies

Questionnaires sent to maintenance managers is a frequently used approach to collect data on software maintenance. This paper reports findings from two studies, carried out at a large Norwegian maintenance organisation, investigating the quality of questionnaire based software maintenance studies.Interesting findings were, among others, that:- The definition of essential terms, for example of 'software maintenance', at the beginning of a questionnaire did not assure a consistent use of the terms by the questionnaire respondents.- Manager estimates of the proportion of effort spent on corrective maintenance were biased when based on best guesses instead of good data. For this reason, the frequently referred studies of Lientz and Swanson (1980) and Nosek and Palvia (1990) may have reported a too high proportion of effort spent on corrective maintenance.