Placement of Menu Choices
Robert W. Allan, Robert W. Bailey, Gregory S. McIntyre, Michelle Bozza · Proceedings of the Human Factors and Ergonomics Society Annual Meeting · 1991
These studies suggest that for certain menus there may be performance advantages in having choices placed on the right side of options. This holds for measures of both speed and accuracy. However, for some menus there is a slight advantage for having choices on the left side. Accuracy levels tended to be better with choices positioned to the right of options. The results suggest that practitioners should consider the relative positioning of options and choices in the design of user interfaces.