An exploratory study on the components and quality of combined assurance in an integrated or a sustainability reporting setting

Purpose - This research complements the corporate reporting literature by exploring the different types of assurance, which companies are using to bolster the credibility of their integrated and sustainability reports. A composite quality measure is proposed and this study aims to provide evidence on how combined assurance quality (CAQ) varies among firms. Design/methodology/approach - Content analysis is used to identify “elements” of combined assurance disclosed in integrated and sustainability reports and company webpages. Results are presented in tabular format and supported by non-parametric tests to evaluate differences in CAQ among firms in more detail. Findings - Combined assurance is framed as a function of the responsibility of the board of directors to ensure accurate, complete and reliable reporting and the characteristics of different internal and external sources of assurance. Overall, combined assurance models are being designed conservatively. They focus mainly on specific disclosures and are guided by a limited number of assurance methodologies or frameworks instead of taking a more pluralistic approach to verification of integrated and sustainability reports as a whole. Research limitations/implications - The study is based on combined assurance practices by a sample of large listed companies in a single jurisdiction. An international comparison of combined assurance and the calibration of the proposed quality measure is deferred for future research. Practical implications - Limitations in existing assurance practices are identified for the consideration of preparers and assurance providers. The quality schematic also offers practitioners, standard-setters and academics an easy-to-apply technique for examining the different elements of a company’s combined assurance model. Social implications - A better understanding of the quality of combined assurance is essential for users’ to place reliance on integrated and sustainability reports and for informing change to existing assurance practices. Originality/value - The study is the first to examine the operation and quality of combined assurance. The method used to gauge assurance quality provides a useful basis for a more detailed empirical study on the relevance of combined assurance.