Professional assessment organizations almost universally endorse the use of multiple measures for making education decisions. In practice, however, the concept of multiple measures is defined and applied in many different ways, depending on how we answer two questions--What counts as a "measure"? and How are the multiple measures combined? Brookhart describes the different approaches to multiple measures that result from the answers to these two questions. In the end, she asserts, the guiding principle for decisions about what measures to use and how to combine them should be the purpose these measures are intended to accomplish. (Contains 1 figure.)