Publication Date

Fall 2015

Degree Type


Degree Name

Master of Science (MS)


Human Factors/Ergonomics


Kevin Jordan

Subject Areas

Industrial engineering


This study investigated the impact of varying the interface design of a software planning tool in a specific domain of the Attitude Determination and Control Operator (ADCO, where ADCO refers to a group or an individual was studied). This study extended a prior study that compared two entirely different interfaces of a software planning tool, LEGACY and NEW, and by which it was found that the NEW interface better matched the underlying domain structure and resulted in improved performance. The current study looked into the impact of varying the levels of presentation of the elements of a plan on user performance in the NEW version of the software planning tool. The plan in the ADCO domain is a sequential grouping of events occurring in a temporal order across a timeline, regulating the movement and orientation of the International Space Station (ISS). Two elements of a plan, Actions and Activities, were organized within three levels, categorized as Increment, Activities, and Actions across the timeline. The two interfaces that were tested in this study were termed the Hierarchical version (delineating each of the three levels of elements, the Increment, the Activities, and the Actions) and the Non-Hierarchical version (presenting only the Increment and Actions). Users of the Hierarchical version tended to perform better on certain task types than did users of the Non-Hierarchical version, but overall the differences in performance were not statistically significant on most tasks. Of all the tasks in the study, performance differed significantly in only one task, favoring Hierarchical version as predicted, in building a plan with the planning tool. The key task that entailed the editing of events with the planning tool did not yield any differences in performance across the two versions.