Companies face growing expectations to disclose climate risks, emissions data and environmental governance practices. However, tracking improvements across the corporate sector can be challenging when the number of companies reporting their environmental performance changes over time.
A study by researchers at Kyushu University in Japan has found that overall climate reporting scores can underestimate progress among companies that disclose information consistently. Published on October 14, 2026, in Corporate Social Responsibility and Environmental Management, the research examined a decade of climate disclosure scores collected by CDP, formerly known as the Carbon Disclosure Project.
CDP is a nonprofit organisation that collects and evaluates corporate environmental disclosures. Although its average scores provide a broad view of reporting trends, changes in the companies included in each assessment can distort comparisons between years.
“Founded in 2000, CDP has built an extensive record of corporate climate disclosure,” said Alexander Ryota Keeley, an associate professor at Kyushu University’s Faculty of Engineering. “While average scores give us a broad picture of reporting trends, the companies being assessed change over time, which can mask progress within individual companies.”
Long-Term Participants Show Greater Improvements
The research team analysed climate disclosure scores for 8,959 companies, covering 37,450 company-year observations between 2016 and 2025. Researchers grouped companies according to whether they remained in the assessment throughout the period or entered or left the reporting population.
The analysis distinguished three groups: companies assessed in both 2016 and 2025, known as stayers; companies assessed in 2025 but not in 2016, known as entrants; and companies assessed in 2016 but not in 2025, known as exiters.
CDP’s eight grades, ranging from D− to A, were converted into a numerical scale from 1 to 8. Using this scale, the researchers found that the overall mean score increased from 5.04 in 2016 to 5.46 in 2025, representing a gain of 0.42 points.
However, the 1,470 companies assessed in both years recorded a considerably larger improvement. Their average score rose from 5.24 to 6.36, an increase of 1.12 points, nearly three times the overall gain.
The difference was largely explained by changes in the reporting population. Companies entering the assessment in 2025 scored below the established participants, reducing the overall improvement by 0.90 points. Meanwhile, companies that had left the assessment scored below the stayers in 2016. Their absence contributed a positive 0.20 points to the overall change.
Together, these population changes offset 0.70 points of the improvement, concealing much of the progress achieved by companies that reported consistently.
“The findings suggest that sustained reporting, supported by strong governance and reliable data systems, may help companies improve their disclosures over time,” Keeley said.
More Detailed Disclosures Associated With Higher Scores
Beyond examining score changes, the researchers investigated whether the content of companies’ written responses was associated with their ratings during 2024 and 2025.
They assessed characteristics including response length, the density of numerical information and the use of qualifying or uncertain language. Combining these measures, the team developed a Textual Detail Index (TDI).
The analysis found that companies providing more detailed responses tended to receive higher scores. This suggests that the depth of information disclosed may be relevant to how environmental reporting quality is assessed.
However, the reported association does not establish that providing longer or more detailed responses directly causes companies to achieve higher scores.
Implications for Companies and Investors
The researchers plan to extend their analysis to other environmental issues, including water management and forests. By combining multiple datasets with newly developed sources, they aim to investigate connections between corporate performance and broader social impacts that individual datasets may overlook.
The findings also offer practical lessons for investors and businesses evaluating climate disclosure. Average scores remain useful for understanding overall trends, but they may not accurately reflect improvements among companies that report consistently.
“For companies, we hope our research highlights the importance of strong governance and a lasting commitment to tracking and reporting data,” Keeley said. “For investors, looking beyond the averages to companies’ governance and long-term commitments can help reveal where progress is being made and where challenges remain.”
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