Purpose The purpose of this study is to explore the comparability of corporate sustainability reporting (CSR) among Spanish State-Owned Enterprises (SOEs) and the evolution of their metrics over time. It specifically examines the extent to which these enterprises adhere to national and international key performance indicators (KPIs), focusing on environmental and human capital indicators. The research aims to understand if regulation alone fosters comparable reporting or if other drivers, such as collaborative platforms and external verification, play a significant role in enhancing the quality and consistency of sustainability disclosures. Design/methodology/approach The study employs a longitudinal analysis of sustainability reports from 25 Spanish SOEs over two fiscal years (2018 and 2021). It utilizes a set of commonly accepted KPIs based on GRI standards and AECA recommendations. The methodology includes Content Analysis: Evaluating four variables for each KPI: reporting presence, inclusion of historical evolution, target setting and unit of measurement. Statistical Testing: Applying Wilcoxon and Mann–Whitney U tests to assess the impact of regulatory changes and other drivers. Herfindahl-Hirschman Index (HHI): Calculating this index to quantify the concentration or dispersion of measurement units to evaluate homogeneity and comparability across the sector. Findings The results reveal a general improvement and homogenization in CSR among Spanish SOEs between 2018 and 2021. Reporting volume increased, and internal comparability improved through better contextualization of data and target setting. While basic environmental and employee metrics are widely reported, complex indicators like Scope 3 emissions remain low. The study identifies three strategic responses: “acquiescence” (proactive alignment), “compromise” (minimalist compliance) and “avoidance” (nonconformity). Notably, membership in collaborative platforms significantly enhances reporting quality and comparability, whereas the impact of external verification remains inconclusive during the studied period. Originality/value The novelty of this study lies in its specific focus on the comparability of CSR within the unique context of State-Owned Enterprises, which serve as hybrid organizations balancing public mandates and market competition. Unlike previous research that often focuses on disclosure presence, this work analyzes units of measurement, historical disclosures and target setting as critical elements for monitoring sustainability performance. It provides empirical evidence on how collaborative platforms act as key drivers for reporting convergence, offering valuable insights for policymakers and standard-setters aiming to improve the effectiveness of non-financial reporting regulations.
Yetano et al. (Thu,) studied this question.