Money managers that have pushed more than $30 trillion into sustainable investments are often basing their decisions on limited and misleading data, according to a new report.

While there’s more environmental, social and governance, or ESG, data available than ever before, most of it’s focused on avoiding risk rather than chasing opportunities, says the report from Generation Investment Management, the $23 billion firm co-founded by former U.S. Vice President Al Gore. The warning for investors: you may not be getting the full picture.

“Data is an important part of how capital is being allocated as a growing number of actors integrate ESG into their investment work,” Felix Preston, director at London-based Generation, said in a phone interview. “There’s a big opportunity and a necessity to raise the bar before people become comfortable with using what is a limited data set.”

While global investors are increasingly tapping into assets that seek to impact climate change, inequality and other world problems, much of the data they’re using can be retrospective, the report says. The information isn’t necessarily clear about how well companies are achieving sustainability goals, such as progress toward net zero carbon emissions.

Data scoring companies highly on one aspect of ESG can sometimes obscure other problems, Preston said. For example, a firm’s greenhouse gas emissions for the past year can be an imperfect proxy for environmental performance, as it often omits supply chain information and the data aren’t always comparable with peers. Scrutinizing the firm’s suppliers and interactions with customers might offer a better reading.

On the bright side, a “next wave” of digital-driven ESG data is emerging, Generation said. That’s likely to prove more forward-looking and relevant for investors as it focuses on new tools such as satellite imagery and blockchain-verified tracking through supply chains. It should also be more easily available to the public, the firm said.

“As long-term investors, we want to know that companies have a clear strategic direction, and we need better data on how they set and work to achieve their targets,” Preston said in a separate release. “We need data on how well companies are doing compared to their public statements.”