VERBAL PROTOCOL ACCURACY IN FAULT-DIAGNOSIS

The study examined whether concurrent and retrospective verbal protoco ls possess the potential to provide a non-reactive and valid account o f the cognitive processes involved in fault diagnosis. With this goal in mind, a group of subjects performed a fault diagnosis task under co ncurrent and retrospective verbalization and in a silent control condi tion as well. In the task, concurrent verbalization led to a considera ble increase in time to completion, but exerted no effect on overall a ccuracy and the adopted strategy. Retrospective verbalization did not have any effect on performance. The strategy-related data obtained und er concurrent verbalization proved to be more valid than those obtaine d under retrospective verbalization. On the basis of the results it is suggested that, where possible, concurrent verbal reports should be c ollected when trying to get a better understanding of the nature of th e fault diagnostic process.