<![CDATA[The Academic Information System Portal (Portal-SIA) serves as the primary digital platform for students' academic activities; however, its mobile interaction is frequently hampered by navigation elements that are too small to operate comfortably. This study aimed to evaluate the usability of Portal-SIA's navigation element sizes and their impact on the efficiency of student interaction. A descriptive quantitative and qualitative approach was employed through a survey method involving 50 students from the Computer Science Study Program at UIN North Sumatra, selected by purposive sampling. Evaluation focused on six User Experience (UX) dimensions: adoptability, usability, efficiency, clarity, error handling, and satisfaction, using a Likert scale 1–5 questionnaire that had been tested for validity and reliability. Results indicated that 91.3% of respondents accessed the portal via smartphone, with the highest complaint rates recorded in the clarity (87.5%), efficiency (87.0%), and error handling (80.8%–82.3%) dimensions, while overall user satisfaction reached only 10.7%. It is concluded that inadequately sized navigation elements impose a significant negative impact on system efficiency and user comfort, consistent with the principles of efficiency of use and error prevention within Nielsen's Usability Heuristics (Nielsen, 1994). This study recommends an interface redesign based on Responsive Web Design (RWD) with touch target optimization conforming to Apple Human Interface Guidelines and Google Material Design standards to enhance the quality of campus digital service interaction. ABSTRAK Portal Sistem Informasi Akademik (Portal-SIA) merupakan platform digital utama bagi kegiatan akademik mahasiswa, namun interaksinya melalui perangkat seluler sering terhambat oleh ukuran elemen navigasi yang terlalu kecil. Penelitian ini bertujuan untuk mengevaluasi usability ukuran elemen navigasi Portal-SIA serta dampaknya terhadap efisiensi interaksi mahasiswa. Penelitian menggunakan pendekatan deskriptif kuantitatif dan kualitatif melalui metode survei dengan melibatkan 50 responden mahasiswa Program Studi Ilmu Komputer UIN Sumatera Utara yang dipilih secara purposive sampling. Evaluasi difokuskan pada enam dimensi User Experience (UX), yaitu adoptability, usability, efficiency, clarity, error handling, dan satisfaction, menggunakan instrumen kuesioner berskala Likert 1–5 yang telah diuji validitas dan reliabilitasnya. Hasil analisis menunjukkan bahwa 91,3% responden mengakses portal melalui smartphone, dengan persentase keluhan tertinggi pada dimensi clarity (87,5%), efficiency (87,0%), dan error handling (80,8%–82,3%), sementara tingkat kepuasan pengguna hanya mencapai 10,7%. Dapat disimpulkan bahwa ukuran elemen navigasi yang tidak memadai memberikan dampak negatif yang signifikan terhadap efisiensi dan kenyamanan penggunaan sistem, sebagaimana dijelaskan oleh prinsip efficiency of use dan error prevention dalam Nielsen Usability Heuristics (Nielsen, 1994). Penelitian ini merekomendasikan redesain antarmuka berbasis Responsive Web Design (RWD) dengan optimasi touch target sesuai standar Apple HIG dan Material Design Google guna meningkatkan kualitas interaksi layanan digital kampus.]]>
