Worthington, A. G., & Wong, P. T. (1979). Effects of earned and assigned grades on student evaluations of an instructor. Journal of Educational Psychology, 71(6), 764-775.
http://dx.doi.org/10.1037/0022-0663.71.6.764
Experimental manipulation of grades assigned to 148 members of an introductory psychology class was performed to determine the effects of actually earned and randomly assigned grades. Earned grade had minor effects on evaluation of the instructor, but assigned grade produced significant modifications in ratings. Less adequate Ss showed greater evaluation rating shifts as a function of manipulations performed. Responses made to attribution questions were consonant with responses to evaluation items. (22 ref) (PsycINFO Database Record (c) 2016 APA, all rights reserved)