In situ repeated measures of affect and cognitive performance facilitated by use of a hand-held computer

The advent of hand-held computers means that it is now feasible to administer standard measures of affect and cognitive performance in field studies without the direct intervention of the investigator. The functional requirements for such an instrument are set out, and a set of programs developed for an electronic Organiser to meet those requirements are described. The programs include alarm scheduling, subjective rating scales, a sleep diary, and choice reaction time and memory search tasks. Compliance rates and usability of the instrument are assessed and judged satisfactory on the basis of examples from three field studies of shiftworkers.