Courtesy of Flickr user nesnet (CC)

The economy is supposedly the least miserable it's been in almost 60 years, but don't try actually telling anyone that.

That's because the so-called misery index, which adds up the inflation and unemployment rates, doesn't really tell us that much about the state of the economy right now. There are three problems with it. The first is that it says lower inflation is always better inflation, when that isn't necessarily the case. The second is that, even seven years after the crisis, the unemployment rate still isn't doing a great job capturing all the people in the labor market who actually want jobs or better jobs. And the third is that you shouldn't put equal weight on inflation and unemployment when the second one is much worse. Add it all up, and you get a metric that paints a much sunnier picture of the economy than real life.

Source: BLS

Now, if you take it at face value, the misery index shows an economy that's partying like it's 1956. That's the last time it was as low as the 5.07 percent it was in September. Unemployment has returned to normalcy at 5.1 percent (and has since ticked down a little more) and inflation is slightly negative. This might not be the best of times, but it's certainly not the worst — right?

Well, yes. But this still overstates how much progress the economy has made since the misery index topped out at 12.74 percent in 2011. The reality is that inflation has been and continues to be too low, which has made it harder for wages to adjust and joblessness to come down in the wake of the crisis. The misery index, though, interprets this as unambiguously good.

Or, to take a more extreme example, it would have said that the fact that prices were falling 10 percent a year during the Great Depression offset some of the 25 percent unemployment, when, in fact, unemployment was that high because prices were falling that much. (That's because lower prices meant lower wages, and debts that weren't any lower were harder to pay back).

The misery index also doesn't notice all the people who have either given up looking for work or who can only find part-time jobs — the "shadow unemployed." It thinks 5 percent unemployment is the same whether in 1997 or in 2015, when that's really not the case.

Indeed, there are still fewer 25- to 54-year-olds — too old, for the most part, to be in school, but too young to be retired — working than there were before the crisis. But more than that, it treats unemployment and inflation as equally bad when economists estimate that the former makes people four times as unhappy as the latter. So the misery index is not only undercounting joblessness, but also underweighting it.

What would be better? Well, probably something that looked at how many people can't find the full-time job they want and how much people who do have jobs are getting paid after inflation. That last part has been a particular problem for a middle class that hasn't gotten much of a real raise in decades.

But in any case, it's time to put the misery index, well, out of its misery.