Abstract: A graphical analysis method (Myors, 1998) was used in 4 experiments. Experiment 1 demonstrated that the keypad of PES psychological experiment system had good t iming accuracy. Experiment 2 showed that the timing accuracy of different keyboa rds varied from 1 to about 40 msec. Those PS2 keyboards had poor performance, es pecially. Experiment 3 demonstrated that the PS2 to Normal and Normal to PS2 converter and the main processor frequency didn't affect keyboard timing accura cy. In experiment 4,3 operators were used and demonstrated that individual's dif ference didn't affect the power of this method. This study demonstrated the use of graphical analysis of timing accuracy, showed that in specific experiment, ti ming accuracy should be checked, in order to decide which kind of keyboard or ke ypad should be used, according to the timing accuracy of the experiment design. A small software named KBTST was provided for the timing accuracy checking.

Key words: graphical analysis method, keyboard, reaction t ime, timing accuracy