<![CDATA[E-commerce platforms require optimal user interface (UI) and user experience(UX) alongside robust technical performance to retain users, particularly inspecialized markets like mother-and-baby products. Initially, the Boonabooe-commerce website exhibited critical deficiencies, achieving a poor SystemUsability Scale (SUS) score of 47.75 and a failing mobile Google Lighthouseperformance score of 41. To address these dual challenges, this study implementeda comprehensive UI/UX redesign using the User-Centered Design(UCD) methodology. A mixed-methods, pretest-posttest evaluation was conductedinvolving 20 respondents, utilizing a novel dual-metric approach thatcombined subjective usability measurement (SUS) with objective technicalauditing (Core Web Vitals via Google Lighthouse). Following the UCDintervention—which encompassed information architecture restructuring, navigationsimplification, and asset optimization—the platform demonstratedremarkable enhancements. Mobile performance surged by 104.8% (from 41 to84), while desktop performance reached near-perfection at 99. Concurrently,the mean SUS score escalated to 87.75, shifting the usability grade from NotAcceptable (Grade F) to Excellent (Grade A). These findings empirically provethat user-centered interface improvements inherently correlate with enhancedmachine-measured web performance. This study contributes a validated dualmetricframework for evaluating e-commerce redesigns, offering actionableinsights for optimizing digital retail environments where cognitive ease, speed,and user trust are paramount.]]>
