This article reports the results of an experiment comparing branch, grid, and single-item question formats in an internet survey with a nationally representative probability sample. We compare the three formats in terms of administration time, item nonresponse, survey breakoff rates, response distribution, and criterion validity. On average, the grid format obtained the fastest answers, the single-item format was intermediate, and the branch format took the longest. Item nonresponse rates were lowest for the single-item format, intermediate for the grid, and highest for branching, but these results were not statistically significant when modeling the full experimental design. Survey breakoff rates among the formats are not statistically distinguishable. Criterion validity was weakest in the branching format, and there was no significant difference between the grid and single-item formats. This evidence indicates that the branching format is not well suited to internet data collection and that both single-item and short, well-constructed grids are better question formats.