This paper applies conceptual engineering to deal with four objections that have been levelled against operationalism in psychology. These objections are: operationalism leads to harmful proliferation of concepts, operationalism goes hand-in-hand with untenable antirealism, operationalism leads to arbitrariness in scientific concept formation, and operationalism is incompatible with the usual conception of scientific measurement. Relying on a formulation of three principles of conceptual engineering, I will argue that there is a useful form of operationalism that does not fall prey to these (...) four objections. (shrink)