Run Scoring Convergence and Parity

As has been well documented league-wide scoring continues to trend down over the last few years. What keeps this an interesting topic is the idea that we’re not fully sure why that’s happening. Savvy vet Ben Lindbergh crushed it out of the park showing that around 30% of the downturn in scoring is due to the enlarged strike zone, which you can almost surely see being tightened up over the coming year. My last piece focused on three true outcome players specifically highlighting how much the strikeout rate has risen over the past decade or so. Today I want to look at this stuff in a couple of different ways to hopefully further the conversation. Let’s start by showing the runs per game spread over each season since 1900:

Each bubble shows a team for each year and I’ve tried to make this emphasize where we see increased density. I’ve also created a poly-trend that gives an idea of over-arching patterns over time. The color-coded sections help differentiate the various eras of the sport and it’s pretty interesting to see how the bands coordinate with the ups and downs of run-scoring almost as if the folks that realized the game evolves put some work into their theory. We’re currently in one of the lowest run scoring periods in league history approaching the doldrums of the 70’s while falling shy of the Deadball Era.

Focusing on that last band to the right it’s interesting that we’re seeing the lows get lower and the highs also shift downward together leading one to believe that this is a league-wide issue and not just some poor devils that aren’t able to figure out which end of the bat to hold which is backed up by the trend shifting downward that much. The thing is, we’re not all that far off from where we were during the pre-Steroid Era which is obviously going to bias some opinions despite obviously standing out from the pack. For me, it’s interesting to see the game get back to it’s roots so allow me to float a hypothesis.

When players are putting up obscene numbers over not just seasons, but over hyper-elongated careers then there is only one subset of teams that will benefit. All teams might reap the benefits of freak players for the first half dozen years of that player’s career, but once the player enters free agency only the hyper rich teams will even have a chance of acquiring these types of players. That is going to lead to inherently less parity in the game as the finite supply of players congregate to the richest teams. With players following a more traditional aging curve it’s not that you will see rich teams not acquiring these players, but these players won’t be as productive for their new teams making them riskier propositions. After all, MLB didn’t care about guys juicing until teams started giving out 10 year, 9-figure deals to a dozen or more players.

In today’s climate the supply of ridiculously good players is smaller and confined to players within the age bands that would see them still with the team that poured resourced into acquisition and development. Let’s see if that shows up at the macro level using a couple of different views:

Unlike the previous chart where we looked at all teams let’s take a look at runs per game for various milestone markers across our data set for each year. Each bubble is going to show the minimum to maximum values with quarterly values mixed in. We see some loose congruence with the first chart, but here we want to see where each of the dispersions tighten up, which should give us a good idea of parity. While you can and should have takeaways from this chart beyond the confirmation that run scoring is dropping I think we can synopsize this stuff better using some other measures:

Similar to the last chart we can use the spread of data across all teams to get an idea of the variation across teams. To do this I used standard deviation (SD), Interquartile Range (IQR) a.k.a. 3rd quarter minus 1st quarter and lastly Coefficient of Variation (CV) which is like SD on steroids because it allows us to control for the mean changing over time (SD/x-bar).

If you’re picking up what I’m throwing down then you realize that as the lines decline over time we’re seeing that the differences between team run-scoring per game is also coming down. We see that during the Steroid Era that “parity” decreased to levels that hadn’t been seen in years while this past season is reaching the levels of parity seen in the late 70’s to early 80’s before collusion allowed some teams to benefit at the peril of others.

As a fan of one of the smallest payroll teams in the history of the game this sort of stuff excites me. When I see that despite MLB’s best efforts to reward huge payroll teams for carrying the torch that penny-pinchers like $Tu $ternberg have as good of a chance as ever to compete with the big boys and all their wonderful toys. I have no idea if these trends will continue to converge and tighten up, but if they do then it allows for teams like the Rays to have as good of a chance as every other team to score runs and win games. Increased parity can only be a good thing if you root for the underdog.

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About Jason Hanselman

Rays fan.
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