The effects of symbology and spatial arrangement on the comprehension of software specifications

Abstract

Seventy-two participants were presented with specifications for each of three modular-sized computer programs. Nine different specification formats were prepared for each program. These formats varied along two dimensions: type of symbology and spatial arrangement. The type of symbology included natural language, constrained language (PDL), and ideograms (flowchart symbols). The spatial arrangement included sequential, branching, and hierarchical versions. The participants answered a series of comprehension questions on each program using only the program specifications. Three types of questions were presented: forward-tracing, backward-tracing, and input-output. Both forward- and backward-tracing questions were answered more quickly from specifications presented in PDL or ideograms than in natural language. Forward-tracing questions were answered most quickly from a branching arrangement, and backward-tracing questions were answered more quickly from branching and hierarchical arrangements. Response times to the input-output questions did not vary significantly as a function of the type of symbology or the spatial arrangement.