TENDY: A Multi-Modal Attendance System Exploring the Friction-Trust Trade-Off¶

Author: Michael Pisman

Published: EECS 255: Advanced Human-Computer Interaction, UC Merced, December 2025

Abstract¶

Attendance systems in higher education are often either slow or easy to game. To study this trade-off, we built Tendy, a cross-platform system that compares three verification approaches: dynamic QR codes (active), Bluetooth proximity (passive), and a biometric liveness check (social). In a small within-subjects pilot study (N=7), reducing user effort did not always improve the experience. The Bluetooth method, although low effort, scored lowest on the System Usability Scale (SUS=59.6) because users had little feedback and felt uncertain. The biometric check took longer but scored higher (SUS=75.7) and was perceived as the most secure.

Research Context¶

Tendy explores the friction-trust trade-off that underpins many authentication and verification scenarios — a recurring theme in the CSED Lab's human-centered security research. The finding that lower effort (Bluetooth) does not automatically translate to higher satisfaction (it scored lowest on SUS) challenges a common assumption in usability engineering and motivates deeper investigation into how feedback, transparency, and perceived security shape user experience.

The system's cross-platform architecture (built with Flutter or a similar framework) and its within-subjects pilot methodology also serve as a methodological template for future HCI studies in the lab.