An Interface Evaluation Model for Usability and Perceived Security

Abstract

The increasing complexity of the digital world has amplified the importance of both security and usability in user interface design. While numerous approaches address these issues separately, there is a lack of perception-oriented evaluation models that integrate usability and perceived security into a single framework. This paper proposes the Usability and Perceived Security Evaluation Model (UPSEM), which enables developers to assess both dimensions simultaneously during the early stages of interface design. UPSEM incorporates hierarchical criteria based on design factors and groups that influence users' look-and-feel-driven perceptions of usability and security. The model employs the Analytical Hierarchy Process, a multi-criteria decision-making method, to evaluate interfaces systematically. Expert evaluations were conducted to validate the model, resulting in a final version that includes 25 design factors categorized into three groups. Notably, the study found no consensus among experts on the existence of a trade-off between usability and perceived security, challenging previous assumptions in the literature. The findings demonstrate that UPSEM provides a practical and scientifically grounded metric for identifying interface features requiring improvement. By offering a structured approach to measure usability and perceived security together, UPSEM supports developers in designing user interfaces that are both usable and secure from the outset.