If the respondent did not have an incident to report, or chose not to
report one, they were instructed to leave the section blank, and continue
to the next section of the questionnaire. In a separate part of the questionnaire,
respondents were asked to report the start and finish times of
their most recent work shift. The study met the ethical requirements
stated in Portaluppi et al. (2008). Participation was anonymous and
voluntary. No information that could be used to identify respondents or
their employers was collected. Questionnaires were returned in a prepaid
envelope.