This study investigated the strategies subjects adopted to solve STEM-equivalent SAT-Mathematics (SAT-M) word problems in constructed-response (CR) and multiple-choice (MC) formats. Parallel test forms of CR and MC items were administered to subjects representing a range of mathematical abilities. Format-related differences in difficulty were more prominent at the item level than for the test as a whole. At the item level, analyses of subjects' problem-solving processes appeared to explain differences as well as similarities. Although there may be good reasons for using constructed-response items in large-scale testing programs, multiple-choice questions of the sort studied here should provide measurement that is generally comparable to stem-equivalent constructed-response items. An appendix presents "Item Stems and Multiple-Choice Options for Each Item Pair."