Computer response time and user performance during data entry

In this experiment, subjects entered data at a computer terminal while the response time of the computer was varied systematically. Long average response times were found to be associated with significantly longer subject “think times”, as was an increase in the variability of the computer's response time. Six subjects entered five-character letter groups under ten different computer response time conditions. The computer response time distributions used had mean values of 2, 4, 8, 16, and 23 seconds, with two different levels of variability at each mean value. User error rate and user typing time were not significantly affected by computer response time, but computer response time was significantly related to user response time (or think time) with this task. User response time increased slowly and gradually with increases in computer response over the range of stimulus values used. Increases in computer response time variability also increased user response time.