ABSTRACT This study synthesises the existing literature on sustainability assurance quality and develops a framework that summarises the current understanding of sustainability assurance quality indicators and consequences. This article begins by examining the definitions of audit, sustainability assurance and audit quality. Next, a systematic literature review is conducted, focusing on the literature regarding sustainability assurance quality published from 2004 to 2024, as well as seminal papers from the fields of sustainability reporting and assurance. A framework is developed using sustainability assurance quality indicators and their associated consequences for assurance quality. Finally, ideas for future research are explored. Promising avenues include inputs, such as assurance providers' subject matter expertise and clients' governance characteristics; process indicators, such as stakeholder engagement and materiality assessment; and output indicators, such as assurance and sustainability reports. In the context category, audit and non‐audit fees, regulations and external stakeholders are also worthy of investigation, as are the consequences for sustainability performance, financial performance and managerial decision‐making. This study contributes to the sustainability assurance literature as it is one of the first to provide a framework of indicators of sustainability assurance quality that includes the consequences of different levels of sustainability assurance quality, while also summarising and comparing existing measurements of sustainability assurance quality.
Xu et al. (Fri,) studied this question.