Usability Quality Model: An Enhancement of Dromey's Model

ABSTRACT Usability is a fundamental software quality attribute that strongly influences user performance, acceptance, and the overall success of software systems. Although Dromey's Quality Model provides an important relationship between high‐level quality attributes and low‐level structural forms through quality‐carrying properties (QCPs), it does not explicitly provide a usability‐focused mechanism that can guide developers and quality engineers in systematically incorporating usability into software products. Existing quality models often treat usability at a broad or abstract level, making it difficult to trace usability concerns to concrete software structures and diagnose usability defects systematically. This creates a gap between high‐level usability goals and practical software evaluation and development activities. To address this gap, this study proposes the usability quality model (UQM) as an enhancement of Dromey's Model. The model was developed by identifying relevant structural forms, extracting usability carrying properties (UCPs) from established usability guidelines and literature, organizing usability into sub‐attributes, and mapping these sub‐attributes to associated high‐level usability attributes. Usability defects were also incorporated to show how the absence or violation of required UCPs can reduce software usability. The proposed model provides a structured linkage among usability attributes, sub‐attributes, UCPs, structural forms, and usability defects. As a proof of concept, the model was applied to common usability defects identified in the literature, demonstrating how usability problems can be traced to structural forms and how appropriate UCPs can guide corrective actions. The results show that UQM can support both top‐down and bottom‐up usability analysis. The proposed UQM extends Dromey's Model into a more usability‐oriented and practically interpretable framework for software quality assessment. It can assist developers, quality managers, and evaluators in embedding usability into software products and in systematically identifying and addressing usability defects. The model also provides a foundation for future empirical validation, real‐world case studies, and automation support for usability‐aware software quality evaluation.