Consider this scenario. Your doctor feels a small lump in your gut. You ask her what to do next. And this is what she says: “There is a test we can order to determine if this lump is an early sign of a pretty rare cancer. The prevalence of this cancer in the general population is less than 2 %. If you have a certain antigen on your white blood cells, though, you are 35% more likely to have the cancer — and we can determine your antigen type with perfect accuracy for 2,000 dollars. Now, 65 % of the people who get this cancer will die in a year. The test for the cancer itself is 98% accurate. When it’s wrong, it shows a false positive 75% of the time and a false negative 25% of the time. If the test comes back positive, we’ll then move to perform a procedure — and 3% of the people who have this procedure will die on the operating table. Another 5 % will suffer side effects that will keep them away from work for a month. But if you have the cancer and you don’t die from the procedure, your chances of survival go up by 40%. The test, by the way, costs 3,000 dollars; and the procedure costs 75,000 dollars”

Then she asks you: “So… do you want to have the test?”

You better know how to answer this question. Because if you don’t, it’s not just you that is in trouble. As a society, we’ve got a serious problem.

Here’s what I mean. For a broad set of reasons that have to do with economics, ideology, and technology, most contemporary governments and societies are pressing the responsibility for decisions like this down on to the individual. And we’re making ourselves feel better about that by championing the cause of individual choice — that’s liberty and autonomy, isn’t it? The ‘information revolution’ democratizes the data — and so why shouldn’t each person make his or her own choice? It can be about whether to take the cancer test. Or about how to invest your 401 (k) funds. Or just about any other decision that used to be delegated to an ‘expert’. We don’t really believe in experts anymore, do we? Call it the ‘Wikipedia Effect’ if you will. Everyone has access to the same data, and I know my own preferences better than any expert possibly could. So I’ll make my own choices thank you very much.

Except smart choices are more than just a combination of data and preferences. Smart choices in an uncertain world demand a sophisticated understanding of risk. In the cancer story, you can’t possibly make the ‘right’ decision, for yourself, unless you have enough knowledge of statistics to calculate the actual risks in each course of action — to take the test, or to do nothing. Yes, it should be the right of every person to make her own decision about what risks she wants to take and what risks she wants to avoid. But she absolutely positively needs to know how to calculate those risks, before she can make that choice. And most of us simply don’t know how to do that.

Now scale the problem up to the level of societal decisions. Should we build another nuclear plant, or burn coal instead? Should we plant genetically modified crops, or accept a higher price for food? We all know how hard it is for groups of people to have thoughtful and intelligent conversations about these kinds of issues without letting emotions take over. But let’s say we managed to take the emotions out of it. The nuclear plant has a risk profile — say, for instance, there is a very small possibility of a major accident that would have horrific consequences, along with a much longer term but smaller risk that comes from the handling of waste products. The coal plant has a shorter term risk profile — more asthma and particulate pollution in the short term, and some risk of contribution to climate change in a slightly longer time frame. How can we possibly have a rational conversation leading to a ‘smart’ decision about this question, unless the people who are participating in that conversation have a shared language that allows them to compare what is knowable about risk?

Anyone who thinks the world’s people have a set of hard choices to make over the next decade — about issues of global importance like energy, climate, food, and finance, as well as individual issues like health care and investing for retirement — should also start learning, and teaching, simple statistics. Not because statistics gives us answers. But because it is a shared language we can use — and had better start to use more effectively — to find our way toward answers.