Comparing API Design Choices with Usability Studies

There are more APIs than ever, and designing APIs that are usable by their target audience is difficult. Work at Microsoft has demonstrated that running controlled usability studies with participants from different personas and analyzing the results of these studies using the cognitive dimensions framework is effective at identifying and preventing usability problems in APIs. This paper presents a generalization of that technique in the form of usability studies of common API design choices. By studying a single design choice from multiple perspectives, we can generalize our results to any API that might be affected by the design choice. We show the feasibility of our approach with an initial study on whether or not to require constructor parameters, and present our current and planned work to study more API design choices.