Portable devices for measuring performance in the field: The effects of sleep deprivation and night shift on the performance of computer operators

The performance of twelve computer operators was measured in the field, on two new portable tests of reaction time, during the first night of the night shift at 0400 h and at the beginning day shift (0800 h), over three successive three-week comparisons. The results were: (i) mean reaction time increased significantly on the night shift as compared with the day: (ii) the adverse effect of the night shift was absent during the first comparison and became increasingly apparent on the second and third replications. These results: (i) provide evidence of inferior performance on the night as compared with the day shift in the field : (ii) show that data from previous studies of sleep deprivation in the laboratory are able to provide a good indication of what was to be expected in the field: (iii) emphasize the need for longitudinal studies in order to assess the true effects of stressful influences.