A number of sustainability rankings have popped up in recent years, and people have debated their value. Well, here's another one: The Roberts Environmental Center of Claremont McKenna College has adapted its Pacific Sustainability Index—which grades the ways that organizations report and publicize their sustainability efforts on their Web sites—to the college market. For several years now, the center's index has been used to grade top companies in various industrial sectors, like aerospace and defense, food services, mining, and so on.

J. Emil Morhardt, a professor of environmental biology and director of the Roberts Environmental Center, says that the index encourages a positive feedback loop in the quest for good PR: "When they start reporting, they tend to look more closely at what they are doing."

The center's report examined the top 50 liberal-arts colleges, as ranked by an organization that produces feedback loops of its own—U.S. News & World Report. The top five colleges in sustainability reporting (drum roll, please): Williams College, Bucknell University, Amherst College, Colorado College, and Gettysburg College. The bottom five: Kenyon College, Centre College, United States Naval Academy, Scripps College, and Occidental College. Undergraduate students at Claremont McKenna did the research for and writing of the report, but Claremont McKenna, which U.S. News ranks 11th among liberal-arts colleges, was not included in the project.

Mr. Morhardt says the Roberts Environmental Center is now working on a sustainability-reporting index for top research universities.

The point is to base the system "entirely on material that is freely available on the Web site," Mr. Morhardt says. "In many ways we may not be capturing true sustainability efforts if they are not reported. We may give a college a very low grade, even if they are doing a lot of stuff, simply because they don't make it available."

But what about a kind of opposite problem? What if the index rates a college highly based on false information, or "greenwashing"? Mr. Morhardt says that the index gives organizations points in some areas for merely mentioning efforts, but more points in other areas for showing data related to efforts.

"We think it's really unlikely that there is greenwashing," he says. "We have been doing this for more than a decade, and we haven't seen a single instance where we have given points to a company for something they actually weren't doing."