It found the issuance of sustainability reports and adoption of voluntary frameworks surged after 2015. But even when following those detailed frameworks, the information didn't necessarily become more granular, especially among companies that recently began issuing sustainability reports. "As reporting spread, reports became less specific, less quantitative (especially after 2015), and fluffier, even as the use of data tables and figures grew," said the study. "Society has invested heavily in voluntary corporate sustainability reporting," said the study. The use of AI large language models enabled the researchers to analyze the thousands of PDFs in the sustainability reports.