Ellis, JasonTran, ChiRyoo, JakeShneiderman, BenButton bars are a relatively new interaction method intended to speed up application use as compared to pull-down menus. This exploratory study compares three command selection methods: pull-down menus, button bars, and user choice of pull-down menus or button bars. Effectiveness was measured in two ways: speed of selection and error rate. 15 participants performed 15 word processor related tasks. Results show that in frequently used functions, such as character attribute selection (bold, italic, u nderline, etc.), button bars are faster. There were no statistically significant differences in error rates between the three interaction methods. (Also cross-referenced as CAR-TR-764)en-USTechnical Report