System response time effects on user productivity

Abstract The present study tested the proposal that reducing computer system response times from a few seconds to sub-second levels results in dramatic increases in user productivity. Subjects completed data-entry and problem-solving tasks using a computer statistical package, under a range of computer response times from 0⋅1 to 5 seconds. Results indicated that some increase in productivity does occur as system response time decreases; however, (1) the size of the effect is considerably smaller than previously indicated, (2) the effect occurred only for data-entry tasks, disappearing in problem-solving situations and declining in strength as the data-entry task became more complex, and (3) the relationship between response time and productivity was linear rather than exponential, as was indicated previously. These results suggest that an attentional'automatic processing model of the user is more appropriate than a model proposing that users do not need time to think between entries to the computer.