A Brief Primer On The 20-80 Scale
The 20-80 scale is the superior scale to rank things. I'm convinced of it.
It's the scale that has been used in baseball scouting circles since long before I was born. Many people credit Branch Rickey with the adoption of the scale for baseball scouting, but it mirrors a normal distribution, which has 99.7% of a sample within three standard deviations of the mean.
I've come to know and use the scale regularly for my work covering prospects, but—like many people in baseball—I've also adopted it to rank things in my day-to-day life. Where most people use a 1-10 scale, us baseball folks use the 20-80 scale.
I think more people should use it.
What typically happens when people use a 1-10 scale is that everything gets tilted towards the 6-10 range. You almost never hear people rate much of anything in the 1-5 range. Sevens are universally handed out with too much frequency, and then when you're left with 8-10 to separate what's good from great, everything gets muddied pretty quickly.
The 20-80 scale helps solve for that, especially if you try and remind yourself of the 68-95-99.7 rule. Most things are going to be clustered in the middle of the scale, with increasing rarity as you approach the extremes on either side.
While ranking things is far more art than science (this is also true of baseball scouting) and we're not always going to be dealing with normal distributions in whatever we're talking about, it's a nice starting point and a great mindset shift.
Below are the grades on the 20-80 scale with common verbiage used to describe them:
- 80 — Top-of-the-scale, elite
- 70 — Plus-plus, double-plus
- 60 — Plus
- 55 — Above-average
- 50 — Average
- 45 — Fringe-average, fringy
- 40 — Below-average
- 30 — Well below-average
- 20 — Poor
Using 55s and 45s are common because you're trying to specify separation among the bulk of your sample within the first standard deviation—the 40-60 range. While some people don't accept any other of these "half grades," I am a fan of using them because some evidence suggests more granular predictions leads to more accurate forecasts. Those who don't like them think that using a 65 instead of a 60 or 70 is "hedging" while I think there could be real value in the grade if you have a genuine reason to split the difference.
Plus, when we're using them to just casually rank our favorite books, movies and fast food joints—it's just more fun. I'll be using the 20-80 scale to rank all sorts of things here on the blog, so I wanted to lay out the basics in a quick post.
If you want to read more about it the 20-80 scale, here are two other good explainers: