July 29, 2014

Umpires: How Do They Impact Total Line Betting in Baseball?

March 7, 2011 by · 4 Comments 

Introduction

I recently read an article about NBA referees and their ability to impact the over/under in total line betting. If more fouls are called, teams shoot additional free throws and play less than optimal defense. MLB umpires may also have the ability to impact the over/under in total line betting. If they call more balls, which result in additional walks, more runs may score. Other umpires may call fewer balls, which decreases walks and potentially reduces the number of runs scored. Bettors would benefit from having more information on the performance of each MLB umpire.

Total Line Betting – Placing a wager on the total number of points, runs, or goals scored in a game.

Over/Under – Betting that the total number of points, runs, or goals will be larger or smaller than expected.

Methodology

I used a web site called Covers.com to analyze the 2010 performance of 62 MLB umpires. Data was collected in the following areas:

  • Games Over Total Line
  • Games Under Total Line
  • Percentage of Games Over Total Line
  • Total Balls Per Game
  • Walks Per Game

Results

Out of the 62 MLB umpires in the sample, eighteen qualified for the Over category. Twelve other umpires were eligible for the Under category. Their performance data is listed in the tables below.

Over

Under

Analysis

48.4% of the sample qualified for the Over or Under category (Over – 29.3%, Under – 19.1%). Jim Reynolds (64.29%), Fieldin Culbreth (63.64%), and Mike Reilly (63.33%) are the most notable members of the Over category. Greg Gibson (21.88%), Jim Wolf (31.25%), and Doug Eddings (33.33%) are the most conspicuous members of the Under category. Surprisingly, there wasn’t a strong correlation between games over, games under, total balls per game, and walks per game.

Conclusions

Almost half of the umpires in this sample qualified for the Over or Under category. Bettors may have an opportunity to make money by carefully examining the performance of each member of an umpiring crew.

Comments

4 Responses to “Umpires: How Do They Impact Total Line Betting in Baseball?”
  1. MK says:

    A few issues worth mentioning. One is that the total already gets adjusted slightly for the extreme umpires. It may be that the adjustment is not optimal (and therefore a better evaluation could still provide one with edge), but just pointing out that bettors/books do look at this already.

    The other main issue is that one season is too small a sample to use. Obviously, if you go too far back, you may be failing to capture a change in style by the umpire, but in general the more data the better.

    Finally, I have found that strike pct. is the best simple predictor of future run scoring for umpires.

  2. kc611 says:

    Is there any way you can do this same analysis for the previous few seasons to see if an umpire does this consistently?

  3. Curt H. says:

    MK and KC611,

    My study would definitely be more meaningful if I analyzed more data. Unfortunately, I usually lack the time needed to do more in-depth research. I’d gladly accept some assistance from either of you. Please contact Mike Lynch if you’re interested.

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