The importance of percent-done progress indicators for computer-human interfaces

A “percent-done progress indicator” is a graphical technique which allows the user to monitor the progress through the processing of a task. Progress indicators can be displayed on almost all types of output devices, and can be used with many different kinds of programs. Practical experience and formal experiments show that prograss indicators are an important and useful user-interface tool, and that they enhance the attractiveness and effectiveness of programs that incorporate them. This paper discusses why progress indicators are important. It includes the results of a formal experiment with progress indicators. One part of the experiment demonstrates that people prefer to have progress indicators. Another part attempted to replicate earlier findings to show that people prefer constant to variable response time in general, and then to show that this effect is reversed with progress indicators, but the results were not statistically significant. In fact, no significant preference for constant response time was shown, contrary to previously published results.