| An Instruction Use Model has been developed which describes the various interactions that a user may have with a set of instructions. The model asserts that in order to complete an assigned task, a user must successfully read, understand and follow the instructions. Although previous research has emphasized the importance of instruction format, this model addresses the instruction content. Specifically, the type and amount of information included in the instructions have been considered. The major objective of this study was to examine how each of the steps in the model is performed for an ill-structured task, such as airline inspection. In airline inspection tasks, written instructions are used to direct and record all of the work that is performed.; First, a laboratory study was conducted to investigate how instructions are used in search tasks. A search task was chosen for this study since search is an integral part of any aircraft inspection task. Then, a field study was conducted to determine what, if any, differences in instruction interpretation persist among aircraft inspectors, and to determine how these experienced inspectors use their interpretations to structure their tasks.; The results from the laboratory study suggest that it cannot be assumed that all participants even read the instructions. Furthermore, the understanding of the instructions seemed to be affected as much by the participants' prior expectations as by the instructions themselves. Finally, performance and strategy were significantly affected by the instructions that participants received. As expected, participants who knew in advance the number of search targets found more targets, were less likely to abandon their search, and were more likely to research particular areas than participants who did not know the number of search targets. However, increasing the specificity of the instructions was found to mitigate the impact of this information, and, in fact, led to a more thorough search.; The results from the field study indicated there are differences in workcard interpretation, even among highly experienced inspectors, and that the type and amount of information included in the instructions impacted the interpretation of the inspection task. However, the results do suggest that inspectors are able to supplement deficiencies in the instructions with experience and domain knowledge. |
