← Search American Economic Review 1980 Bias in Economics Education Research from Random and Voluntary Selection into Experimental and Control Groups John J. Siegfried; George H. Sweeney Sources openalex Cite APA 7 MLA 9 Chicago (author–date) Harvard Elsevier Harvard (JFE, JBF…) The Accounting Review Academy of Management American Marketing Association INFORMS (Management Science) Copy citation Copied ✓