For effective program evaluation, it is necessary to specify a counterfactual state, i.e., what would have happened without the program. Conventional approaches to program evaluation, preoccupied with technical and value issues, fail to address directly the need for counterfactual arguments....

The economic importance of "knowledge work" has become widely accepted. Less widely accepted are the changes knowledge work requires in how we manage performance. This paper explores the differences between knowledge work and more traditional physical and managerial work, in the context of...