Divergence and aggregation of ESG ratings: A survey

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  1. Arianna Agosto
    ,  
  2. Alessandra Tanda
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Abstract

Purpose

This paper reviews the existing literature on Environmental, Social, and Governance (ESG) ratings divergence and aggregation methods. It highlights the challenges posed by inconsistent ESG ratings and their implications for investment decisions.

Design/methodology/approach

The study conducts a comprehensive review of prior research focusing on ESG ratings, examining their correlation levels and the methodologies employed to assess corporate sustainability. It also investigates traditional aggregation techniques and modern machine learning approaches used to address these inconsistencies.

Findings

The review reveals that ESG ratings exhibit a low level of correlation across different providers, raising concerns about their reliability as investment indicators. Although some studies propose advanced aggregation methods to enhance accuracy, significant gaps remain in understanding how to effectively consolidate ESG information to create a dependable sustainability indicator.

Originality

This paper provides a critical analysis of the current state of ESG rating methodologies, emphasizing the need for improved aggregation strategies. It underscores the importance of future research in leveraging ESG data to develop more consistent and reliable measures of corporate sustainability.

Corresponding author
Alessandra Tanda
0000-0002-6885-899X
Grant information

This project has received funding from the European Union’s Framework Programme for Research & Innovation as part of the COST Action CA19130 ‘Fintech and Artificial Intelligence in Finance’ (FinAI), as supported by the COST Association (European Cooperation in Science and Technology). This project also received funding from the European Union - Next Generation EU, Component M4C2, Investment 1.1, Progetti di Ricerca di Rilevante Interesse Nazionale (PRIN) – Notice 1409, 14/09/2022- BANDO PRIN 2022 PNRR. Project title: 'Climate risk and uncertainty: environmental sustainability and asset pricing'. Project code 'P20225MJW8', CUP: F53D23009320001. And has also received funding the European Union-NextGenerationEU, in the framework of the GRINS -Growing Resilient, INclusive and Sustainable (GRINSPE00000018). The views and opinions expressed are solely those of the authors and do not necessarily reflect those of the European Union, nor can the European Union be held responsible for them.

The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Copyright
© 2025 Arianna Agosto (Co-Author); Alessandra Tanda (Corresponding Author, Co-Author) Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

First version published
Latest version published
Revised

Amendment

We have rewritten the introduction and several key sections to better integrate the reviewers’ suggestions, providing a clearer explanation of the motivation behind our work and the main contributions it offers. In particular, we have updated the section on the literature review to incorporate more recent and relevant studies, ensuring a more comprehensive overview of the existing research. Additionally, we have added a dedicated section outlining the methodology used to select the papers included in our analysis, thereby improving the transparency and reproducibility of our literature survey.
We have also expanded the discussion on the metrics most commonly used to assess divergence in ESG scores. Specifically, in section 5 of the revised manuscript, we clarified that most studies quantify divergence by analysing the low pairwise correlations between ESG ratings assigned by different providers. Among the most frequently used measures, the Pearson correlation coefficient is often adopted due to the continuous nature of ESG scores, although rank-based alternatives like Spearman's coefficient are also used. Furthermore, we summarised studies that incorporate unsupervised techniques such as Principal Component Analysis (PCA) to explore the structure of ESG data.
In response to the reviewer’s comments, we emphasised the absence of a standardised and widely accepted framework for evaluating the performance of ESG score aggregation methods. This lack remains a significant limitation in the field. Finally, we outlined several directions for future research in the concluding section of the revised manuscript, including the application of clustering techniques to group companies based on their ESG profiles and the investigation of methods to enhance the interpretability of the weights used in aggregated scores. We also discussed the trade-offs involved in using complex, computationally intensive tools - such as Shapley values - for explainability, which may not always offer clear benefits in terms of predictive performance.

Comments

Authors & roles

Arianna Agosto

Department of Economics and Management, University of Pavia, Pavia, Lombardia, 27100, Italy

Roles
Co-Author, Conceptualization, Formal Analysis, Funding Acquisition, Investigation, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing

Alessandra Tanda

Department of Economics and Management, University of Pavia, Pavia, Lombardia, 27100, Italy

Roles
Corresponding Author, Co-Author, Conceptualization, Methodology, Writing – Original Draft Preparation, Writing – Review & Editing
0000-0002-6885-899X

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