We describe an experiment to test the hypothesis that Fitts' throughput is independent of the speed-accuracy tradeoff. Eighteen participants used a mouse in performing a total of 5,400 target selection trials. Comparing nominal, speedemphasis, and accuracy-emphasis conditions, significant main effects were found on movement time (ms) and error rate (%), but not on throughput (bits/s). In the latter case, failure to reject the null hypothesis of "no significant difference" (i.e., .05 < p < 1) is viewed as evidence supporting the constant-throughput hypothesis. Author Keywords Fitts' law, throughput, speed-accuracy tradeoff ACM Classification Keywords H.5.2 User Interfaces. Input devices and strategies
I. Scott MacKenzie, Poika Isokoski