Number Blindness

“When the facts are on your side, pound the facts. When the law is on your side, pound the law. When neither is on you side, pound the table.” – old legal adage of unclear origin

Recently I’ve been finding it rather hard to go on Facebook. It seems like every time I log in, someone I know has chosen that moment to start a political debate that is going poorly. It’s not that I mind politics or have a problem with strong political opinions, but what bugs me is how often suspect numbers are getting thrown out to support various points of view. Knowing that I’m a “numbers person”, I have occasionally had people reach out asking me to either support or refute whatever number it is that is being used, or use one of my posts to support/refute what is being said. While some of these requests are perfectly reasonable requests for explanations, I’ve gotten a few recently that were rather targeted “Come up with a reason why my opponent is wrong” type things, with a heavy tone of “if my opponent endorses these numbers, they simply cannot be correct”. This of course put me in a very meta mood, and got me thinking about how we argue about numbers. As a result, I decided to coin a new term for a logical fallacy I was seeing: Number Blindness.

Number Blindness: The phenomena of becoming so consumed by an issue that your cease to see numbers as independent entities and view them only as props whose rightness or wrongness is determined solely by how well they fit your argument

Now I want to make one thing very clear up front: the phenomena I’m talking about is not simply criticizing or doubting numbers or statistics. A tremendous amount of my blogging time is spent writing about why you actually should doubt many of the numbers that are flashed before your eyes. Criticism of numbers is a thing I fully support, no matter whose “side” you’re on.

I am also not referring to people who say that numbers are “irrelevant” to the particular discussion or said that I missed the point. I actually like it when people say that, because it clears the way to have a purely moral/intellectual/philosophical discussion. If you don’t really need numbers for a particular discussion, go ahead and leave them out of it.

The phenomena I’m talking about is actually when people want to involve numbers in order to buffer their argument, but take any discussion of those numbers as offensive to their main point. It’s a terrible bait and switch and it degrades the integrity of facts. If the numbers you’re talking about were important enough to be included in your argument, then they are important enough to be held up for debates about their accuracy. If you’re pounding the table, at least be willing to admit that’s what you’re doing.

Now of course all of this got inspired by some particular issues, but I want to be very clear: everyone does this. We all want to believe that every objective fact points in the direction of the conclusion that we want. While most people are acutely aware of this tendency in whichever political party they disagree with, it is much harder to see it in yourself or in your friends. Writing on the internet has taught me to think carefully about how I handle criticism, but it’s also taught me a lot about how to handle praise. Just like there are many people who only criticize you because you are disagreeing with them, there are an equal number who only praise you because you’re saying something they want to hear. I’ve written before about the idea of “motivated numerancy” (here and for the Sojourners blog here), but studies do show that ability to do math rises and falls depending on how much you like the conclusions that math provides….and that phenomena gets worse the more intelligent you are. As I said in my piece for Sojourners “Your intellectual capacity does NOT make you less likely to make an error — it simply makes you more likely to be a hypocrite about your errors.”

Now in the interest of full disclosure, I should admit that I know number blindness so well in part because I still fall prey to it. It creeps up every time I get worked up about a political or social issue I really care about, and it can slip out before I even have a chance to think through what I’m saying. One of the biggest benefits of doing the type of blogging I do is that almost no one lets me get away with it, but the impulse still lurks around. Part of why I make up these fallacies is to remind myself that guarding against bias and selective interpretation requires constant vigilance.

Good luck out there!

One thought on “Number Blindness

  1. When we believe something, we have a strong suspicion that the numbers are going to back us up*, so we go looking for them. Or send a numbers Golden Retriever out to look for them. We hope those numbers will convince others. I am more likely to use them defensively, not so much to convince an opponent, but to at least give them pause and not pursue a particular line quite so aggressively. (I do the same with logic and history, actually.) I seldom have the feeling that I’ve found a particular set of numbers that say “There, that settles it.” I’m reading a book by a Swedish economist showing that their socialism has not been as good to them as they think. That’s what I want to hear, and I’m tempted to poke some Bernie Bros with it. Yet I also know that someone might have at least a partial answer to him.

    That said, I know that we tend to remember things that support our position, and forget those that undermine it, and I imagine am susceptible to that as well. We must make an exception for the weak arguments of our opponents, because they come back as straw men or stereotypes so often. The most likely situation which will allow us to question our numbers is when better evidence shows that something a _little_ different is true. “No, most women don’t do that, but an overwhelming number of short women do, which skews the data for the whole group.” Ah. I see. Yes, that makes sense. Fascinating.

    *Most popular use of statistics can find its echo in baseball. Bill James, in giving yet one more argument to those who wanted to claim that some players are good even though their numbers don’t show it. “If you are good, you’re going to leave a trail of numbers somewhere.”


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