The JIS Z 9090 standard was used to measure the accuracy of three GPS loggers with added noise as anticipated under conditions of use, and the error was calculated. An economic evaluation was made by calculating loss from the error. For signals, five reference stations located in Tokyo Metropolis and Kanagawa Prefecture were used. The calibration error σc and error σ were found according to JIS Z 9090 supplements 2 and 3, and the measurement error σT was calculated from their sum. Functional limits were set from usage conditions, and the loss entailed by use was calculated. The results enabled an economic evaluation including the accuracy of the three GPS loggers to be made.

With the number of sufferers from occupational accidents and diseases currently trending upward, the national administration is again calling for the implementation of effective safety and hygiene education tailored to individual worker conditions. It will now be possible to respond to this call for education swiftly by applying the error root mean square method to the evaluation of questionnaires,which presented difficulties in the past. This is because the absence rate, which represents the frequency of occurrence of occupational accidents and diseases, can be predicted directly from a worker's error root meall square distance as obtained from the questionnaire results, and because itemized diagnostics enable education to be targeted effectively for the individual worker. Repetitions of a cycle consisting of education based on the results of the individual worker's itemized diagnostics, followed by action, then questionnaire evaluation,and then prediction of DIFR and further itemized diagnostics will provide powerful support for the ongoing labor safety effort and will lead to a reduction in occupational accident and disease rates.