Mark Twain once said “there are three kinds of lies: lies, damned lies and statistics.” He would have loved recycling statistics.

I don‘t say that because I believe that recycling statistics are deliberately misleading. Most of the ones that I have seen represent an honest attempt to assess the current level of recycling at the state or local level. Done properly, they are an important way to measure progress. Done badly, they are simply press releases.

Unfortunately, as states raise recycling targets, I expect we will see more attempts to claim greater progress then has occurred. Part of the problem is that most state targets are not based on any sensible analysis of achievable recycling rates. Instead they are based on the politics of the moment. In almost all cases, that politics is based on shooting as high as possible. Aggressive recycling targets will lead to aggressive recycling reporting. After all, everyone wants to meet their goals and we all want to be number one. To help you separate the wheat from the leachate, I offer the following guidelines for analyzing recycling rate claims, especially the ones that are unusually high.

The first thing is look for if the recycling rate just covers run of the mill garbage, the kind we call “municipal solid waste.” This is the stuff that you and I and businesses generate and that local governments are directly responsible for managing. Or does it also include construction and demolition debris and other forms of nonhazardous solid waste? Construction and demolition materials tend to be more easily recyclable. Including them is a great way to increase recycling rates. Frankly, I don’t care if they are included in the recycling rate, but I do care if that fact is not mentioned. How can we fairly compare programs that cover paper and cans and yard waste with those that also include rubble?

Secondly, is the rate for “diversion” or for recycling? Diversion can mean a lot of things. If it is not explicitly defined, the numbers are probably fudged. Sometimes, for instance, energy from waste is considered diversion from landfilling. Energy from waste is a perfectly fine technology. However, the report should spell out if it is included in diversion from landfilling and if so whether the ash generated by the facility was recycled or landfilled.

The third and perhaps most important thing to look for is specific tonnage numbers. Does the report give tonnages for the amount of garbage that was generated, how much was recycled and how much was landfilled? Does it give specific tonnage figures by material? The more specific and transparent the data, the more likely the recycling rate truly measures what is occurring.

Finally, does the state allow for a source reduction credit? A number of states do this, including my home state of Maryland. In this case, a local government’s recycling rate can be increased by several percentage points to give it credit for the use of source reduction techniques. Promoting backyard composting and using pay as you throw systems to pay for solid waste management are examples of these techniques. Giving credit for these activities is admirable, but increasing the recycling rate by arbitrary percentages is misleading.

Some cities do a good job of reporting, some don’t. Philadelphia does a short but straightforward report. Seattle gets the gold medal for thoroughness. But heed the advice of one of my favorite presidents when you are looking at recycling reports, “Trust, but verify.”