Bruised Peach Problems

There's a fun little nugget that, among American men aged 20-40 and over 7 ft tall, 17% play in the NBA. I say "nugget" not "fact" because this is potentially untrue, possibly because it neglects to consider that (until 2020) the NBA measured player heights including their shoes, itself a nugget that confirms the worst suspicions of everyone who dates men and uses dating apps.

But I digress. If we stacked enough measurable traits together, we could create a category in which even 50% of its members do play in the NBA – I'm making up the details but imagine something like [American men] [aged 20-40] [and over 7 ft tall] [and able to bench press 185lb 1x20] [and able to vertical jump 20 inches] [and played high school basketball].

Now: if you find someone in this category, and they're not in the NBA, can you say "well, they could clearly play in the NBA, if they wanted to?"

No you couldn't, or rather, you shouldn't. The more obviously NBA-worthy traits someone has stacked on top of each other without also being in the NBA, the more that we should suspect that they have some hidden traits that prevent them from NBA-ing: for example, maybe they're the kind of person who always chokes under pressure.

I think this is a common category of error, but I don't know a common name for it. It's got a little bit of selection bias and a little bit of adverse selection and a little bit of your grandmother telling you "if it looks too good to be true, it probably is."

Pending better ideas, I'm going to call it the bruised peach problem. There's a famous paper in economics about the difficulty of distinguishing a "lemon" (a bad used car) from a "peach" (a good one), given that the seller has a bunch of secret information that you as a buyer don't.

My claim is that an amazing-looking second-hand car that's priced well below market and still hasn't sold is disproportionately likely to be a lemon, or, more evocatively, an internally bruised peach.

Here's some examples:

• if you meet someone implausibly attractive and also single, there's arguably a higher chance they're a bruised peach than someone who is single for very obvious reasons. The flip side of this is that if you're single and people don't understand why, it might be better to convey to them a legible reason for it.
• if you find an apartment that's priced way under market and in a great location and with lots of space (etc etc etc), you should worry that it either 1) has a hidden but terrible flaw, 2) is a scam
• I have lots of friends who seem like they "could" earn a lot more money than they do, based on their skills and pedigree. The more such skills a person has, the more I suspect they actually couldn't in practice earn more money than they do, because of some invisible internal anti-making-money-trait.

I feel a bit weird writing this post, because sometimes a peach is really a peach, and I don't want to be causally responsible for anyone missing out on a find. But mostly, if it looks too good to be true, it probably is, and specifically it probably has a hidden trait that makes up (down) for its visible ones.