Poor math skills lead to bad politics and policy

We Americans are really bad at math.

The trend, I'm afraid, is getting worse - with sorry implications for the nation's welfare.

Back in 2003, the National Assessment of Adult Literacy calculated that one in five Americans was innumerate (the "numbers" equivalent to illiterate). These folks could not compute a weekly paycheck based on an hourly wage rate. They couldn't calculate a 15 percent meal tip.

Another group had only rudimentary skills. Only half the people surveyed could figure out whether a car had enough gas to make it to the next gas station after being shown a fuel gauge, the car's average MPG, and the mileage to the nearest pump.

So what, you say? That was 2003. This is 2017. Now (praise Apple!), we have iPhones to calculate the tip. Our car's dashboard tells us in plain English how many miles' worth of gas we have.

Problem solved, right?

Well, not exactly. By reducing the occasions where Americans must do calculations themselves, technology may render them even more helpless when it comes to using math to evaluate political or policy questions. Let me review a few dire examples from recent news.

Look, I recognize the cases I'm about to cite have as much do with emotions getting in the way as they do with raw ineptitude with numbers. It's human nature to cherry-pick facts that confirm our biases - and to let one anecdote, one bit of cable news video, outweigh a mountain of statistics. But consider: Were people more adept at math, might they pay at least a little more heed to numbers that clearly invalidate a position?

President Trump successfully framed the last election as about a crisis of "American carnage." In fact, national violent crime rates reached a 30-year low in 2014. Murder rates did move up in 2016; the overall number of murders was so low that a badly bloody year in Chicago and a few other cities proved enough to move the national rate up a tick. You know . . . how statistics work. But we live in a world where crimes that once might have merited a paragraph in your local newspaper now play in awful loops all day long on cable news. This creates a free-floating anxiety that no stream of positive statistics can calm.

The new head of the federal Office of Management and Budget made a $2 trillion error in the first budget he submitted to Congress. He double-counted a predicted surge in tax revenues. Called on this, he shrugged. America barely blinked. Even worse, the very idea of that $2 trillion gusher is predicated on one of American politics' most stubborn absurdities: the Laffer curve. This core tenet of conservative theology holds that when you cut taxes in a major way, you unleash an economic surge that throws off enough tax revenue to make the net effect at least neutral, at best positive. That this has never happened with a federal tax cut doesn't shake the faith. Now, it's true that tax cuts can trigger growth that offsets some of the potential dip from the cuts, but only some. Acolytes cite such evidence as though it validates the Laffer curve. Actually, it disproves the theory.

Trump loyalists maintain that polls indicating low approval ratings are meaningless because "the pollsters were totally wrong about the last election."

Well, no, they weren't. People routinely confuse the numbers estimating the probability of a Trump victory (35 percent at 538.com on the Sunday before the election) with estimates of his percentage of the vote, which weren't that far off. On the Sunday before, Nate Silver's crew had Trump's percentage of the national vote pegged at 45.4. The actual number on Nov. 8: 46.1 percent. Hardly a huge miss.

What's more, the probabilities were dead on. The way Trump narrowly ran the table in key swing states really was no better than a one-in-three chance. The New York Times' Upshot team likened Trump's chances to the likelihood of an NFL kicker missing a 37-yard field goal. Two Sundays after the election, NFL kickers missed 11 extra points, a slighter shorter kick. Such things happen, just not a majority of the time.

By the way, partisan blinders that shut out math are not the province solely of the right. Bernie Sanders' fans, for example, showed a stunning ability to ignore basic delegate-counting arithmetic.

Here's a common Harrisburg trope: "The Philadelphia School District spends nearly $3 billion a year. How can that not be enough?" This is usually said in a that-settles-it tone; the only thing missing is the mic drop.

Well, when a school system educates eight times as many students as the next biggest, its spending logically will be the biggest by far. The only number that really matters is per-student spending. That's a simple calculation (spending divided by number of students). Do it, and you'll find that Philly's spending ranks middle of the pack statewide and at the low end among big cities nationally.

If Philly spent as much per student as, say, Radnor Township on the Main Line, its budget would be nearly $4.5 billion.

Again, it's a simple calculation. Then why, year after year, does it prove beyond the ken of Harrisburg types to do it?

If the answer isn't arithmetical incompetence, the alternative explanations are even more damning.

Chris Satullo is a former Inquirer editor. centersquarephil@gmail.com