Roberts M – OBJECTIVE AND SUBJECTIVE METHODS FOR EVALUATING THE USABILITY OF SCHEMATIC MAPS 2023

Description

Research shows many users prefer visually appealing but sub‑optimal schematic map formats and often judge usability by superficial features (e.g. line colours, octolinearity) rather than performance cues. Roberts and colleagues conducted an internet study with 649 participants (274 classed as potential experts) who rated nine London Underground schematic maps varying by design rule (octolinear, multilinear, curvilinear) and priority (stylized, geographical, compact). Strong main effects emerged: octolinear and stylized (simple trajectories) designs were rated highest across groups. Differences between experts and non‑experts were marginal—experts were only slightly more sensitive to trajectory simplicity and marginally less likely to hold empirically falsified theories (e.g. octolinearity as a universal gold standard). Individual rating coherence and sophistication did not reliably distinguish experts. The study concludes subjective non‑expert ratings are poor guides to objectively optimal designs; expert opinion adds limited value without a consensual, evidence‑based body of principles. It calls for continued empirical testing and development of validated usability measures and design frameworks.