For those of us who love quizzes, environmental footprint calculators are as irresistible as they are sobering (not many of us get a “you rock” result). And in addition to point­ing out our Yeti-size impact on the planet’s resources, they illustrate some communications essentials.

American Public Media’s Consumer Consequences “game” may be the most elaborate calculator. It looks great, lets you create an avatar to move through your world, and covers your whole life, from energy use to food to shopping. But it fritters away its initial high engagement factor with a nonfunctional avatar (why offer it if it doesn’t do anything?) and clunky interface. The result (the number of planets it would take to support humankind if everyone lived like you) is clever and alarming, but the site doesn’t take advantage of that by asking you to do anything specific.

The Nature Conservancy’s calculator is nearly as comprehensive, but much faster and provides helpful advice on how to answer the questions accurately. The tips at the end are solid, but a little too general—what would really deliver is advice specific to users’ answers.

StopGlobalWarming.org takes an inspiring approach. Instead of calculating damage, it calculates the savings you can achieve in dollars and pounds of CO₂ emitted by doing specific things. It’s not the prettiest calculator, but it got me out my chair and taking immediate action.

The lessons for communicators: don’t get fancy if you can’t fully deliver on expectations; ask people to do something specific—preferably right now; and show people what they can achieve, not just what they’re doing wrong. As for your own footprint, take the StopGlobalWarming.org actions, then calculate your impact. The result won’t hurt as much. First published October 2007 in Words That Work.