See research paper on efficiency wage theory – Review of public personnel administration.
Jeannette Taylor and Ranald Taylor working hard for more money or working hard to make a difference? Efficiency wages, public service motivation, and effort, Review of public personnel administration, March 2011, 31: 67-86
Part 2: Empirical Evidences
Once you have provided a theoretical framework for your analysis, you can link them to the “real world”. Here, you need to search the literature for studies/research conducted either supporting those theories or against those theories.