ANGLE OF HARD-COPY AND TEXT-EDITING PERFORMANCE

Three experiments evaluated the effect of angle of hard copy on text-e diting performance. In the first, as the angular discrepancy between t he hard copy and VDT screen increased, so did editing times and errors ; experienced computer users generally outperformed naive users. The s econd experiment replicated the first but added text highlighting and a secondary task involving cancellation of a text/background screen re versal as factors. This study confirmed many of the results of the fir st. The secondary task response times showed consistent but nonsignifi cant effects of angle. Whether or not the line currently being edited was highlighted did not affect performance. The results of the third e xperiment suggested that having the hard copy orthogonal to the line o f sight is important; in addition, it should also be adjacent to the V DT screen. These data argue for adjacent configurations that are norma l to the line of sight. Subjective preferences generally supported thi s contention.