Workload and Performance: Orthogonal Measures

During an attempt to corroborate historical error data with recently gathered data on subjective workload values, it was noted that the data not only failed to show any degree of correlation, but gave strong evidence to support arguments that the workload and error measures are orthogonal (totally independent). This paper discusses several explanations of the observed phenomenon. A hypothesis is advanced that error free performance is strongly dependent upon task procedure construction, while workload is dependent upon subtask difficulty and situational stresses.