新興国における監査委員会の実効性：化粧的会計・サステナビリティ・保証品質に関する洞察

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🔬研究者:監査委員会属性とサステナビリティ保証選択の関係について、新興国データで因果的示唆を与える実証研究として参照できる。

🏢実務担当者:監査委員会の構成（女性比率・会議頻度・専門性）がサステナビリティ開示と保証品質を左右する点を、自社の開示ガバナンス設計に活かせる。

🏛政策担当者:サステナビリティ報告・保証の質を高めるには、監査委員会の構成や外部モニタリング（機関投資家）の役割を制度設計に組み込む視点が有用。

This PhD thesis provides a comprehensive examination of audit committee effectiveness in relation to cosmetic accounting, sustainability reporting, and assurance quality. It comprises three interrelated essays that explore the role of audit committee characteristics in Nigeria. The first essay examines "Audit committee attributes and cosmetic accounting practices: Evidence from an emerging economy." The second essay investigates "Audit committee attributes and financially material sustainability reporting: Evidence from an emerging market." The third essay explores "Audit committee attributes and companies’ choice of sustainability assurance providers: New insights from an emerging market." Together, the three essays contribute to a deeper understanding of how audit committees influence corporate transparency, accountability, and the quality of financial and non-financial reporting. The first essay in this thesis investigates the interplay between audit committee attributes and cosmetic accounting practices (CAP), with a focus on the moderating influence of political connections in a developing country context characterized by weak governance codes. Using a sample of 980 firm-year observations for firms listed on the Nigerian Exchange Group (NGX) for the period 2011–2020, I uncover complex relationships between audit committee characteristics and CAP. The analysis reveals that audit committee size and audit committee co-option have a positive relationship with CAP, while audit committee legal expertise, audit committee gender diversity, and audit committee chairperson have a negative relationship with CAP. Furthermore, audit committee gender diversity and audit committee chairperson reduce CAP and co-opted committees increase CAP, when its directors are politically connected. The findings are robust to alternative measures and controlling for potential endogeneity issues. This essay contributes to the academic literature by elucidating how audit committee attributes and political connections can either constrain or enable CAP within an emerging market, providing a foundation for enhancing accountability and disclosure quality. The findings carry implications for corporate stakeholders, policymakers, and regulators, highlighting the critical need for effective governance mechanisms to combat impression management and promote corporate transparency. Building on the research gap identified in the first essay, the second essay extends the analysis by exploring the role of audit committee attributes in influencing the disclosure and financial materiality of sustainability reporting based on the sustainability reporting standards of the Sustainability Accounting Standards Board (SASB). I use a sample of 980 firm-year observations of firms listed on the Nigerian Exchange Group (NGX) for the period 2011–2020 and employ two proxies for sustainability reporting, disclosure of sustainability reporting and financially material sustainability information. The findings indicate that larger audit committees, more frequent audit committee meetings, and the presence of female members on the audit committee are positively associated with sustainability reporting. However, an audit committee chaired by a shareholder representative is negatively associated with sustainability reporting. No significant association is observed between audit committee financial expertise and sustainability reporting. This essay provides critical insights into the current state of sustainability information disclosure and financially material sustainability reporting in Nigeria, highlighting the impact of recent regulatory reforms aimed at promoting such practices. The findings offer valuable guidance for regulators, standard-setters, and practitioners on leveraging audit committees to enhance the disclosure of financially material sustainability information. The third essay investigates the association between audit committee attributes and firms’ choice of sustainability assurance providers, as well as the moderating role of institutional ownership in this relationship. Using a sample of 980 firm-year observations from publicly listed companies on the Nigerian Exchange Group (NGX) over the period 2011–2020, I predict and find that audit committee size, meeting frequency, and financial accounting expertise are positively associated with the choice of Big Four audit firms (Big4) as sustainability assurance providers. In contrast, audit committee gender diversity and chairperson exhibit positive but not statistically significant relationships, suggesting that formal governance structures alone may be insufficient to influence firms’ selection of Big4 assurance providers. The analysis further shows that institutional ownership weakens the positive effect of audit committee size on the choice of Big4 firms as sustainability assurance providers, indicating that strong external monitoring can partially substitute for internal governance mechanisms. The findings are robust across alternative specifications and endogeneity concerns, supporting the validity and reliability of the main results. I contribute to the sustainability assurance literature by providing empirical evidence on how audit committee attributes influence the selection of Big4 firms as sustainability assurance providers in an emerging market context and offers practical insights for regulators and corporate boards seeking to enhance the credibility of sustainability reporting.

• openalex https://doi.org/10.82348/our-archive.00449first seen 2026-11-12 05:12:21 · last seen 2026-11-13 05:20:19