The Accommodated Proportion of a Potential User Population: Compilation and Comparisons of Methods for Estimation

Abstract

Aircraft cockpits, desktop consoles, and other workspaces have traditionally been designed to accommodate individuals with all anthropometric features (dimensions) within specified percentile ranges (e.g., 5th to 95th). Because of correlations between features, the accommodated proportion of the potential user population (Pa) is not readily apparent or usually determined. Due to the importance of this statistic, however, a wide variety of methods for estimating Pa have been proposed and developed. Cataloging, describing, and comparing methods for calculating the accommodated proportion of potential users is the purpose of this report. This effort is timely, as the proposed “B” revision of MIL-STD-1472 (Human Engineering Design Criteria for Military Systems, Equipment, and Facilities) requires that equipment designed to accommodate 90 percent of a user population on all anthropometric variables.