Quantification of Technical Manual Graphics Comprehensibility

Current graphic practices for technical manuals, as set forth in military specifications, standards, handbooks, and other publications, are rarely based on objective evidence that they improve utility and comprehensibility. Methods based on valid data are not currently available either for establishing requirements for procuring technical manuals or for objectively measuring the effectiveness of a particular illustration in supporting the job performance of technical personnel. To begin development of empirically based guidelines and objective measurement techniques to increase the usability of illustrations in technical manuals. The general approach was: 1) To identify a limited set of features which can be hypothesized as facilitating or inhibiting the usability of illustrations; 2) To construct technical illustrations displaying variations of these features; and 3) To measure the performance of Navy technicians extracting selected information from the illustrations.