What is Error Ratio

Human information processing (HIP) performance using the working memory can be assessed by two types of indicator when an HIP task is carried out. One is error occurrence and the other is HIP time taken when the HIP task is carried out using the working memory. Errors are classified into the error which is caused by the task requirement exceeding some human’s limitation or the error which is caused by carelessness even though all of human’s limitations still allow enough capacity to do the task (Reason, 1990). The former is regarded as an error that is caused by the lack of the HIP ability in order to do the required information processing. The latter is regarded as an error that is caused by the temporary reduction of some HIP ability such as attention. Even though there are many kinds of factors of error generation, from the view point of HIP, error can be considered to be caused by the relationship between the required quantity or quality of the information processing and the HIP ability. The characteristics of HIP can be considered to influence error generation directly. In this chapter the characteristics of HIP related to the error are illustrated with the results of the experiments. (Karashima, Okamura & Saito, 1994, Karashima & Saito, 2001)