D. T. キャンベル（Campbell）は評価研究における社会実験（social experiments）の重要性を指摘し続けたが，彼の評価研究におけるバイアス問題の解決に関する多大な貢献を称賛しつつも，そのアプローチは広く社会プログラムの評価には応用することが出来ないことが評価研究のコミュニティから指摘されている。
”In the end, however, Campbell’s experimental approach to evaluation became just one small part of the field. Critics challenged his Experimenting Society particularly the notion that experimental methods were preferred for evaluation. They argued that experimental methods were insufficient to address social problems in a world where policy practice is entangled with politics, economy, and social pressures; questioned the importance of noncausal questions and nonexperimental methods; complained that experimentally based knowledge was not fully implemented in solving social problems; and pointed out limitations of experimental methods. Eventually the field of evaluation rejected Campbell’s Experimenting Society as too narrow and Utopian, preferring a broader vision of the role of evaluation. Even so, because bias remains a central problem for evaluation, the solutions Campbell offered will be his greatest legacy” (Alkin, M., 2004, Evaluation Roots, pp. 82-83; Alkins, M., 2013, Evaluation Roots, 2nd ed., p. 63).