The error as a defect and as a mean of controlling the activity in work situation

In activity, the error is often evaluated in a negative manner, as the absence of succes. But the error may also have a positive role in that it reveals the characteristics of the activity: so, its knowledge can be a way to control the action, as shown, in particular, the regulatory model for which the action is regulated based on differences in purpose. It is precisely from this model that will be organized this paper. It sugests this can be a framework for analysing the error by showing the work of particular significance. The introduction refers to some general knowledge on the study of error. The second chapter justifies the need to coordinate the study of error to that of activity. The following sections are organized around several themes that mark out the analysis for this coordination: setting goals, assessing the error with the issues of detection and diagnosis, the possible exploitation of the error. A final section addresses the role of the operator characteristics in the production and the management of the error. The conclusion discusses the interest of exploiting the dual character of error for the analysis of activity and on how this exploitation.