An Investigation of Stress Level and Human Reliability Analysis of Two Security Companies in Taiwan

This article presents the results of an evaluation and comparison study of three subjective techniques for determining human reliability under stress for work performed at two Taiwanese security companies. Stress levels at security companies were estimated by using the Unified Tri-service Cognitive Performance Assessment Battery and 40 participants from two similar-sized companies. Experiment results (memory searching task and mathematical processing task) indicated that the participants were under high levels of stress. Three subjective techniques (Success Likelihood Index Method, Technique for Human Error Rate Prediction, and Human Error Assessment and Reduction Technique) for estimating human error probability were evaluated and compared by using 20 experts for six tasks. The comparison criteria are interjudge consistency and accuracy. Of the three human error probability tests studied, the Technique for Human Error Rate Prediction and Success Likelihood Index Method were more consistent than the Human Error Assessment and Reduction Technique. The same relationship occurred in the comparison of accuracy. Thus, the Human Error Assessment and Reduction Technique may need to be modified in some way if it is to be useful. It was already known that this technique required modifications in error-producing conditions and nominal human unreliability. Our work presents additional evidence to substantiate this.