How Much Do Ratios Regress In Season?

by
August 28, 2026


THOMAS CORDY/PALM BEACH POST / USA TODAY NETWORK via Imagn Images

I thought I’d had a smart idea. I wanted to see how “dead” affected a league’s standings as the season drew to a close. With managers quitting their teams for various reasons, I wanted to see how the rate stats for underperforming teams changed. The counting stats needed to move up or down the standings are easier to calculate for each league, but rate stat movement is a bit of a mystery. I expected the bottom teams to go after counting stats and ignore their ratio categories. They did not. Instead, I verified regression remains unbeaten … probably.

I wanted to look at a previous season’s data and see how the ratio stats changed over the last month of the season. That information is not available. I got the bright idea to compare the performance of the top and bottom teams over the last month to find any movement.

For the analysis, I examined the 900-team NFBC Main Event, which provides weekly standings. I created nine groups based on their standings from four weeks ago. Then I found how the rate stats from each group performed on average. Here are the results

Rate Stat Performance Over the Last Month Based on Initial NFBC Main Event Ranking
Initial Standings AVG ERA WHIP
1 to 100 -0.0018 0.042 0.013
101 to 200 -0.0015 -0.005 0.004
201 to 300 -0.0008 -0.028 0.004
301 to 400 -0.0008 -0.007 0.005
401 to 500 -0.0003 -0.030 0.003
501 to 600 0.0002 -0.054 -0.002
601 to 700 0.0001 -0.041 -0.001
701 to 800 0.0001 -0.084 -0.007
801 to 900 0.0010 -0.076 -0.009

Across the board, the best teams saw their ratios worsen while the worst teams saw their ratios improve. There will be exceptions, but fantasy managers should not expect bad teams to get worse.

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I have three possible explanations, with the truth probably lying in some combination.

  1. Regression. The players on the top teams have been overperforming, and as they regress downward, the top teams will be dragged down.  The same goes for the bottom teams. Their underperformers will start getting hot and improve their managers’ standings.
  2. The top teams have solid ratios and now can take more chances on suspect hitters and pitchers as they focus on their counting stats.
  3. Bad players work themselves off dead teams. An underperforming player stuck in these ignored lineups could head to the bench or minors, so only the “good” players continue to contribute.

On top of the three listed reasons, fewer teams may be dead in the Main Event than in other formats. If a manager drops $1750 on a team, they may feel they have to play out the league. Also, third place pays out, so more teams may be trying to get in the money. I decided to look at the NFBC Online Championship, which has a $350 entry fee, but ended up with the same results.

Rate Stat Performance Over the Last Month Based on Initial NFBC Online Championship Ranking
Initial Standings AVG ERA WHIP
1 to 288 -0.0015 0.0057 0.0105
289 to 576 -0.0014 -0.0059 0.0076
577 to 864 -0.0009 -0.0188 0.0041
865 to 1152 -0.0007 -0.0209 0.0046
1153 to 1440 -0.0004 -0.0161 0.0052
1441 to 1728 -0.0002 -0.0381 0.0006
1729 to 2016 -0.0001 -0.0441 -0.0009
2017 to 2304 0.0001 -0.0406 -0.0011
2305 to 2592 0.0005 -0.0512 -0.0025
2593 to 2880 0.0009 -0.0765 -0.0081

Same pattern. While it’s too late to use these findings for this season, managers can understand that all teams regress to the middle as the season goes on.





 

Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won four FSWA Awards including on for his Mining the News series. He's won Tout Wars three times, LABR twice, and got his first NFBC Main Event win in 2021. Follow him on Twitter @jeffwzimmerman.

2 Comments
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Corey2Member since 2021
11 days ago

I think its mostly hypothesis #3.

0
slingerMember since 2016
9 days ago

Although the regression to the mean pattern is similar, ERAs appear to generally get better in both leagues.

0