Sustainability assurance and provider choice: a meta-regression analysis

Purpose This paper aims to assess the cumulative evidence on the determinants of sustainability assurance (SA) reports and the choice of assurance provider quality. It addresses the contradictory and inconsistent findings of past studies conducted over the past two decades. Design/methodology/approach The authors undertake a meta-regression analysis that enables systematic, comparative assessment of the variables associated with the choice of SA and the type of assurance provider. The authors undertake a chronological analysis with the aim of identifying systematic differences in the empirical evidence across distinct time periods. Findings The results indicate that there is very little evidence to support many of the expected associations between commonly studied predictor variables (namely, measures based on agency and corporate governance conceptions) and the choice of SA and the assurance provider type. As a result, research on this topic does not make as effective a contribution as might be expected. There is, however, a time period difference. The authors find results from studies using company data prior to 2010 are significantly different from those using post-2010 data. The results indicate the decision to publish SA to be significantly associated with companies in the oil industry and utilities, and larger organisations where agency costs tend to be higher. Obtaining assurance from a higher-quality provider is found to be associated with companies in environmentally sensitive industries and in stakeholder-oriented countries. Practical implications The study shows that as yet there is not sufficient evidence to support expected results. Users of the research should be aware of this, and researchers should know that more work is needed. The authors suggest researchers take greater care in the choice and comparability of variable measurement and expand the conceptual base when selecting predictor variables. Social implications Companies need to be more transparent and accountable to critical stakeholders such as report users and regulators, and the latter should be more aware that the organisational practice of SA and choice of service provider have changed over time and are increasingly open to agency and other cultural biases. Originality/value To the best of the authors’ knowledge, this is the first study to apply meta-regression techniques for understanding the body of literature on SA and provider choice.