"Although the extent to which companies have provided independent assurance over their CSR disclosures has steadily grown, the study also revealed that the majority still did not. Although the pool of CSR assurance providers has widened to become more inclusive, contrary to the expectation that the dominance of the Big 4 audit firms would gradually be eroded, the study found that the Big 4 audit firms were actually consolidating their position in this area."

[COMMENTARY] I’ve long held that CSR disclosures should be independently audited — as per financial statements — and the results available to all stakeholders. Though the above study was South African based, it provides some insight into the possible state of CSR auditing today. Hopefully, similar studies will be done, particularly in the USA, Europe, and Japan.
The Evolution of Corporate Social Responsibility Assurance – A Longitudinal South African Study, by Barry Ackers, February 25, 2017, Social and Environmental Accountability Journal, UK.