Communicating about sustainability inevitably means communicating about statistics—something I think it’s fair to say we all struggle to do well. How do you make huge numbers, often measuring things that are invisible to us (carbon dioxide emissions, kilowatt hours), meaningful enough to make an impression on people?

Carolyn addressed this earlier this year, providing a neat summary of the use of Fermi problems to tackle the challenge. I’m happy to add another inspiration source, a recent Fast Company column by Made to Stick authors Dan and Chip Heath, “The Gripping Statistic: How to Make Your Data Matter.”

As the Heaths point out, some communicators realize that “big numbers fuzz our brains,” and understand that they need to be translated to something that relates to everyday life. Attempts to solve the problem often don’t pan out, however. One particularly useful (if disgusting) example from the column:

Building intuition about numbers is different from shocking people with numbers. We’ve all heard stats like this one (which is real): 27 billion disposable diapers are used each year in the United States—enough to stretch all the way to the moon and back seven times. What to say about this? For starters, it would be a funny joke to play on the astronauts.

But notice that the astronomical analogy blocks any useful intuition. Would we feel better, for instance, if the diapers only stretched to the moon and back once? That would be just as gross, yet it would mean that six out of every seven families had given up disposables.

The problem here is not just relatability (while we all understand that the moon is far away, most of us haven’t been there) but utility: illustrating the abundance of disposable diapers this way doesn’t give us any insight into how big a problem this is or how we might address it. As the Heaths say, “A good statistic is one that aids a decision or shapes an opinion.”

For  example? There are a couple in the column. If anyone has others, I’d love to hear them.

Universities are not generally known as hotbeds of modesty, but you’d never guess that by looking at university sustainability websites.

One of the most common flaws is a lack of focus on what the university is doing, and how its institutional values and educational commitments influence its approach to sustainability. Instead, many sites speak in generalities about what sustainability is (I’ve lost count of the number of sites that quote the U.N. definition on their home page or in another prominent position), why it’s important, and what people can do about it.

The problem is, there are countless resources online for that kind of information, and generalities on why it matters don’t engage people in sustainability initiatives. When key audiences come to a university site they want to know what actions the university is taking, how those actions relate to the university’s mission and community responsibilities, and how people on campus can participate. That’s why, as I said in a previous post, the best sites put school policies, goals, and strategy front and center.

If you’re going to define sustainability, do it in terms of what it means to Whatever U. Describe why efforts in each sustainability area are important in Whatever U’s context (cold winters, water shortages, etc.). Tailor tips to campus goals and your specific audiences (there’s little point in telling students who live in dorm rooms how much carbon they can cut by weatherizing their home). And cite your achievements—they tell people that your sustainability message is more than talk.