When I was working, I was a member of our LGBT employee affinity group for 12 years. We used the CEI as a tool in getting company management to understand the value of policy changes and how they compared to other companies.
Corning, Inc. is an international company with many factories and R&D installations around the world. The business model is based on devoting a higher percentage of profits to R&D efforts in order to create technologies and high margin products that no one else has done. In order to do that, a very highly talented and capable workforce is needed. These days younger folks are more sensitive to the social conscience of their employers, or potential employers. Scoring well on the CEI helps to reinforce that point. When I was there, we scored 100% for many consecutive years as the criteria continually ramped up.
Note that HRC also does a number of other studies:
For full disclosure, after I retired I held office in our local HRC group for about 2 1/2 years…