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Psychological scaling of expert estimates of human error probabilities: Application to nuclear power plant operation
a much lower percentage response for symptoms and discomfort than the questionnatre, and, just as with visual acuity and refraction, there was no difference between the exposed and reference groups or between the men and women. The exposed subjects were found to be overcorrected in terms of presbyopla addition in relation to work distance As regards ocular examination findings, low frequency rates were noted for pathological lens opacities Opacities of this kind were slightly more frequent among the VDT operators than among the referents, but the difference was not statistically significant. There were no other differences in the ocular findings of the exposed and reference groups
Information processing and transmission by man 18.1.6 (100795)
Langan-Fox, C.P., and Empson, J.A,C. 'Actions not as planned' in military airtraffic control. Ergonomzcs, 28.11, 1509-1521 Observations were made of the errors made by eight air-traffic controllers over two periods each of 2"5 h Errors were classified using a recently devised classification of motor-program errors (Reason, 1979), and all the controllers were observed under three conditions of workload, and performing two ostensibly similar air-traffic tasks. More errors were found with increasing workload, but only in one of the tasks. This was interpreted in terms of the pacing and tune stress inherently imposed m that task. The assessment of error incidence seems a good candidate as a non-intruswe measure of workload. Analysis of errors in terms of Reason's typology showed no interaction with any of the other variables. The association of errors with the use of particular pieces of equipment demonstrated ergonomic deficiencies which may have otherwise remained unnoticed. It seems that error auditing may also be a useful investigative technique in ergonomlc assessment. 18 1.7 (100798)
Raouf, A., and Elfeituri, F. Inspector accuracy as effected by incoming quality, complexity of inspection task and time allowed for inspection In: Trends in Ergonomics/ Human Factors II, Ed by R.E. Eberts and C.G. Eberts. North-Holland, Amsterdam, 1985, pp 9 3 - 1 0 4 . Accuracy of visual inspection is influenced by three major sets of factors: inspector related factors, task related factors, and factors related to the
76
Applied Ergonomics
March 1987
environment It is generally agreed that inspectors make two types of errors, namely reporting a defective component when it is not defective (type I error), and failing to report a defect (type 1I error) This paper presents the findings of an experimental study which examined potential inspection accuracy differences, in terms of two types of errors when varying the following factors (1) different incoming quality levels having polsson distribution (5 levels), (2) different levels of task complexity (2 levels), (3) different times allowed to complete inspection (2 levels). Findings are based on the results obtained using 15 subjects while performing a computer controlled simulated inspection task 18 1.8 (100800)
Stringer, P.G., and Riley, D.D. Pilot error accidents. A Total System Approach to analysis. In Progress for People. Proceedings of the Human Factors Society 29th Annual Meeting, Baltimore, Maryland, 29 Sep - 3 Oct 1985, Ed by R W Swezey. The Human Factors Society, Santa Monica, California, Vol 1, 1985, pp 5 2 6 - 5 3 0 . New technology systems are radically changing cockpit designs. But little information is available about the best use of the capabilities provided by these new systems to optimise crew performance and minimise pilot error accidents. This paper describes a method for using pilot error accident analyses to identify areas in which aircraft design improvements would be desirable and cost effective A Total System Approach can be used to extract generic information from the accident records while protecting the privileged information contained in those records. Accident reports, grouped for analysis by experienced specialists, can be scrutmised to expose areas in which flight and/or mission requirements exceed pilot capabilities Technology needs, aimed at either reducing flight/mission requirements or enhancing pilot capabilities, can then be identified. A better balance of these requirements and capabilities can be expected to reduce pilot error accidents, resulting in cost savings which would offset the cost of new system design development. 18.1.9 (101405)
Comer, K., Gaddy, C.D., Seaver, D.A., and Stillwell, W.G. Psychological scaling of expert estimates of human error probabilities. Application to nuclear power plant operation. In: Progress for People. Proceedings of the Human Factors Society 29th Annual Meeting, Baltimore, Maryland, 29 Sep - 3 Oct
1985, Ed by R.W. Swezey. The Human Factors Society, Santa Monica, California, Vol 1, 1985, pp 57 60 The US Nuclear Regulatory Commission and Sandaa National Laboratories sponsored a project to evaluate psychological scaling techniques for use in generating estimates of human error probabilities. The project evaluated two techniques direct numerical estimation and paired comparisons. Expert estimates were found to be consistent across and within judges. Convergent validity was good, in comparison with estimates in a handbook of human reliabihtv Predictive validity could not be established because of the lack of actual relative frequencies of error (which will be a difficulty inherent in validation of any procedure used to estimate HEPs). Apphcation of expert estimates in probabillstic risk assessment and in human factors is discussed.
Factors affecting perceptual-motor processes in man 18 1 10 (100898)
Bassett, J., and Spillane, R. 'Jet lag' as an occupational stressor.
Journal of Occupational Health and Safety A ustraha and New Zealand, 1985, 1.1, 2 6 - 3 2 . This research began as a study of occupational stress in aircraft cabin crew. One of the stressors to which cabin crew are exposed is ctrcadlan dysrhythmla or 'jet lag', which was assessed physiologically by urinary cortisol excretion rates and psychologically by mood ratings. Twenty-eight cabin crew (17 male and 11 female) collected urine samples and rated moods for eight days which included a tour of duty from Sydney to Los Angeles and return. Two tours with different stopover times m Los Angeles were studied to gauge the effect of circadian dysrhythmia. The period spent in Los Angeles and the flight home were associated with significantly elevated cortisol levels while mood ratings showed a clear and consistent pattern of increasing fatigue and decreasing efficiency throughout the tour. The major factor accounting for these changes appears to be circadian dysrhythmia. The imphcations of these findings for personal productivity, rosterlng and stopover times are noted. 18.1.11 (100904)
Knave, B.G., Wibom, R.I., Voss, M., Hedstrom, L.D., and Bergqvist, U.O.V. Work with video display terminals among office employees. I. Subjective
Information processing and transmission by man 18.1.6 (100795)
Langan-Fox, C.P., and Empson, J.A,C. 'Actions not as planned' in military airtraffic control. Ergonomzcs, 28.11, 1509-1521 Observations were made of the errors made by eight air-traffic controllers over two periods each of 2"5 h Errors were classified using a recently devised classification of motor-program errors (Reason, 1979), and all the controllers were observed under three conditions of workload, and performing two ostensibly similar air-traffic tasks. More errors were found with increasing workload, but only in one of the tasks. This was interpreted in terms of the pacing and tune stress inherently imposed m that task. The assessment of error incidence seems a good candidate as a non-intruswe measure of workload. Analysis of errors in terms of Reason's typology showed no interaction with any of the other variables. The association of errors with the use of particular pieces of equipment demonstrated ergonomic deficiencies which may have otherwise remained unnoticed. It seems that error auditing may also be a useful investigative technique in ergonomlc assessment. 18 1.7 (100798)
Raouf, A., and Elfeituri, F. Inspector accuracy as effected by incoming quality, complexity of inspection task and time allowed for inspection In: Trends in Ergonomics/ Human Factors II, Ed by R.E. Eberts and C.G. Eberts. North-Holland, Amsterdam, 1985, pp 9 3 - 1 0 4 . Accuracy of visual inspection is influenced by three major sets of factors: inspector related factors, task related factors, and factors related to the
76
Applied Ergonomics
March 1987
environment It is generally agreed that inspectors make two types of errors, namely reporting a defective component when it is not defective (type I error), and failing to report a defect (type 1I error) This paper presents the findings of an experimental study which examined potential inspection accuracy differences, in terms of two types of errors when varying the following factors (1) different incoming quality levels having polsson distribution (5 levels), (2) different levels of task complexity (2 levels), (3) different times allowed to complete inspection (2 levels). Findings are based on the results obtained using 15 subjects while performing a computer controlled simulated inspection task 18 1.8 (100800)
Stringer, P.G., and Riley, D.D. Pilot error accidents. A Total System Approach to analysis. In Progress for People. Proceedings of the Human Factors Society 29th Annual Meeting, Baltimore, Maryland, 29 Sep - 3 Oct 1985, Ed by R W Swezey. The Human Factors Society, Santa Monica, California, Vol 1, 1985, pp 5 2 6 - 5 3 0 . New technology systems are radically changing cockpit designs. But little information is available about the best use of the capabilities provided by these new systems to optimise crew performance and minimise pilot error accidents. This paper describes a method for using pilot error accident analyses to identify areas in which aircraft design improvements would be desirable and cost effective A Total System Approach can be used to extract generic information from the accident records while protecting the privileged information contained in those records. Accident reports, grouped for analysis by experienced specialists, can be scrutmised to expose areas in which flight and/or mission requirements exceed pilot capabilities Technology needs, aimed at either reducing flight/mission requirements or enhancing pilot capabilities, can then be identified. A better balance of these requirements and capabilities can be expected to reduce pilot error accidents, resulting in cost savings which would offset the cost of new system design development. 18.1.9 (101405)
Comer, K., Gaddy, C.D., Seaver, D.A., and Stillwell, W.G. Psychological scaling of expert estimates of human error probabilities. Application to nuclear power plant operation. In: Progress for People. Proceedings of the Human Factors Society 29th Annual Meeting, Baltimore, Maryland, 29 Sep - 3 Oct
1985, Ed by R.W. Swezey. The Human Factors Society, Santa Monica, California, Vol 1, 1985, pp 57 60 The US Nuclear Regulatory Commission and Sandaa National Laboratories sponsored a project to evaluate psychological scaling techniques for use in generating estimates of human error probabilities. The project evaluated two techniques direct numerical estimation and paired comparisons. Expert estimates were found to be consistent across and within judges. Convergent validity was good, in comparison with estimates in a handbook of human reliabihtv Predictive validity could not be established because of the lack of actual relative frequencies of error (which will be a difficulty inherent in validation of any procedure used to estimate HEPs). Apphcation of expert estimates in probabillstic risk assessment and in human factors is discussed.
Factors affecting perceptual-motor processes in man 18 1 10 (100898)
Bassett, J., and Spillane, R. 'Jet lag' as an occupational stressor.
Journal of Occupational Health and Safety A ustraha and New Zealand, 1985, 1.1, 2 6 - 3 2 . This research began as a study of occupational stress in aircraft cabin crew. One of the stressors to which cabin crew are exposed is ctrcadlan dysrhythmla or 'jet lag', which was assessed physiologically by urinary cortisol excretion rates and psychologically by mood ratings. Twenty-eight cabin crew (17 male and 11 female) collected urine samples and rated moods for eight days which included a tour of duty from Sydney to Los Angeles and return. Two tours with different stopover times m Los Angeles were studied to gauge the effect of circadian dysrhythmia. The period spent in Los Angeles and the flight home were associated with significantly elevated cortisol levels while mood ratings showed a clear and consistent pattern of increasing fatigue and decreasing efficiency throughout the tour. The major factor accounting for these changes appears to be circadian dysrhythmia. The imphcations of these findings for personal productivity, rosterlng and stopover times are noted. 18.1.11 (100904)
Knave, B.G., Wibom, R.I., Voss, M., Hedstrom, L.D., and Bergqvist, U.O.V. Work with video display terminals among office employees. I. Subjective