Conclusion
In this paper, we use the unique setting of CSR restatements to provide evidence on (1) whether CSR assurance improves CSR reporting quality, and if so, in what manner and (2) whether accounting providers improve CSR reporting quality to a greater extent than non-accounting providers. Results indicate that CSR assurance improves CSR reporting quality by identifying inaccuracies in prior reports and improvements to definitions, scopes, and methodologies that require restatements for comparability. As predicted, such quality improvements are increased when provided by accounting firms. In fact, results suggest that accounting providers are not only more likely to identify reporting inaccuracies, but do so in a timelier manner and prevent future inaccuracies. Results also indicate that CSR reporting frameworks (e.g., GRI) are not a substitute for obtaining CSR assurance in terms of improving reporting quality. More specifically, this finding suggests that while adopting GRI reporting standards helps enhance CSR reporting quality through prompting non-error CSR restatements, it does not appear to have the same impact on error discovery and correction as assurance-related activities. These results extend previous research documenting capital market benefits of CSR assurance (Pflugrath et al., 2011; Casey and Grenier, 2015; Cheng et al., 2015) and are inconsistent with previous extreme criticisms of CSR assurance (see Section 1).