Proper Response Times and Design Factors Influencing User Satisfaction with Diverse Touch Tap Operations for the Smartphone

Abstract

Background Tap operations by finger touch are the most basic and important functions in smartphones. However, existing guidelines on their response times have not yet reflected recent users’ expectations of high speed, and various types of touch taps and their response times. Methods In order to investigate proper response times and design factors influencing user satisfaction with response speeds, this study established several measures for tap operations and their responses, and measured the performances through high-speed video analysis on four smartphones. Then, an experiment was performed to evaluate user satisfaction with system responses, and the relationships between the measured performances and user satisfaction were analyzed. Results The speed satisfaction of visual feedback did not show a big difference if the response time was less than 0.2 seconds. For high satisfaction, offline apps should initially respond within about 0.2-0.4 seconds and be completed within approximately 1.0 seconds. In the case of online apps, showing progressive changes while the apps are loading was more important. Similarly, smooth movement patterns influenced speed satisfaction in deleting a memo or rotating a picture. For a double tap, the proper time interval between two taps and the expansion starting time was approximately 0.1 seconds. Also, the satisfaction was high when a long tap was initiated after 0.7 seconds and text input was responded to within 0.1 seconds. Conclusion This study presented fundamental performance guidelines on satisfactory response times for various touch tap operations and their responses. In addition, important design factors affecting user satisfaction of speed were derived.