The Display Mode and the Combination of Sequence Length and Alphabet Size as Factors in Keying Speed and Accuracy

Four combinations of sequence length and keyset size were selected to give 22.3 bits of information per sequence in each case. Two visual display conditions were used with each of the four combinations: a continuous display where the sequence remained in view throughout keying, and an on-demand display where the sequence disappeared once keying started but could be made to reappear when the subject pressed a button. Results indicate that keying was faster and more accurate with the short sequences and the large keyset, in contrast with the long sequences and the small keyset. These differences were particularly large where the ondemand display was used.