Process use refers to changes in attitude, thinking, and behavior that result from participating in an evaluation. Process use includes individual learnings from evaluation involvement as well as effects on program functioning and organizational culture. The "Encyclopedia of Social Science Research Methods," in an entry on operationalization, affirms the scientific goal of standardizing definitions of key concepts. It notes that concepts vary in their degree of abstractness, using as an illustration the concepts human capital versus education versus number of years of schooling as moving from high abstraction to operationalization. The entry then observes: "Social science theories that are more abstract are usually viewed as being the most useful for advancing knowledge. However, as concepts become more abstract, reaching agreement on appropriate measurement strategies becomes more difficult." Abstraction is "useful" for advancing knowledge and building theory. Process use is abstract, and its very quality of abstraction makes it difficult to reach agreement on how to measure (operationalize) it. The entry continues: "Social science researchers do not use [operationalization] as much as in the past, primarily because of the negative connotation associated with its use in certain contexts." One way to address problems of operationalization is to treat process use as a sensitizing concept and abandon the search for a standardized and universal operational definition. This means that any specific empirical study of process use would generate a definition that fit the specific context for and purpose of the study, but operational definitions would be expected to vary. Process use is best understood and used as a sensitizing concept. Judging the concept's meaningfulness through the lens of operationalization misconstrues its utility. In this article, the author looks at process use as a sensitizing concept and examines what other articles in this issue reveal about process use as a sensitizing concept. (Contains 2 figures and 2 tables.)