Deriving and analyzing performance strategy in a two-dimensional drawing task

This research determined the performance strategy of six expert users on an engineering drawing task. Six experts were required to complete one engine ering drawing task during which the whole drawing process was video-recorde d. By reviewing the videotape together with the keystroke data, the drawing process of each subject was repeated by the experimenters to analyze menta l pauses and operation sequence in terms of execution steps (functional uni ts) separated by large mental pauses. These execution steps were grouped in to 13 unit tasks to classify a subject's performance strategy into two majo r types. Different unit tasks and performance strategies were compared by s everal performance measures: physical time, small mental time, large mental time, and error time. These performance time measures were well predicted by a U-shaped model using the unit task (sequence) number as the predictor. This could have been caused by the proposing of a feasible solution at the initial stage, and the increase in working memory load caused by the gradu al increase in graphic components and constraints between components toward the end of the drawing process. Finally, a flowchart formulated with the u nit tasks was utilized to summarize the strategy of each individual subject . A flowchart constructed using this approach can be regarded as a conceptu al model in future training of novice users when learning a new computer la nguage or software. Relevance to industry This research determined the performance strategy of six expert users on an engineering drawing task. It demonstrated that flowcharts derived from the analysis of unit tasks can be utilized to describe the strategy of each in dividual subject. The same analytical approach can be adapted to build simi lar models for other software packages and application domains. (C) 2000 El sevier Science B.V. All rights reserved.