Abstract
This paper describes a methodology for testing the usability of a digital library. The paper also presents the results from using this methodology on a specific library of technical manuals. The testing process involves timing subjects while they look up facts in comparable libraries of online and paper documents. They are timed for both how long they take to find a desired manual in the library and how long they take to find a desired fact in a chosen manual. Next, the subjects fill out a questionnaire on which type library they prefer using and why. The objective time results and the subjective preferences are compared and analyzed.