Using Math to Calculate Baseball Statistics

Every baseball fan is familiar with the statistics of the game. They help us to decide who we are going to draft in our fantasy league, right? But does the average fan know how those stats are calculated? Simple algebraic equations are used when calculating these baseball stats. Check them out:

Batting Average Calculation

Batting average is the most common statistic used to decide how effective a batter is, and it’s a simple calculation.

Number of hits / Number of at bats

If it was in your textbook, the formula for batting average formula would be:
X/Y = batting average
X = hits
Y = number of at bats

Yes, it’s that’s simple.

While that is a good gauge as to the efficiency of how well a player is doing offensively, it only takes hits and at bats into consideration. What about walks or sacrifices? That brings us to our next calculation…

On Base Percentage (OBP) Calculation

On base percentage is a better judge of how efficient a batter really is because it measures the percentage of times that they get on base, not only hits.

It is calculated like this:
(Hits + Walks + Number of times hit by pitch) / (At bats + Walks + Number of times hit by pitch + Sac flys)

If that was in your textbook, the formula for on base percentage would be:
(X + Y + Z) / (A + Y + Z + B)
A = at bats
B = sac flys
X = hits
Y = walks
Z = number of times hit by pitch

Enough of the offensive statistics. Time to get into pitching stats.

Earned Run Average (ERA) Calculation

While batting average is the most common gauge for hitters, earned run average is the most common gauge for pitchers. It tells how many earned runs they give up per nine innings.

Here’s how to calculate a pitcher’s ERA:
(Number of earned runs allowed x 9) / Innings pitched

In your textbook the formula for earned run average would look like this:
(X x 9) / Y = Earned run average
X = number of earned runs allowed
Y = number of innings pitched

WHIP Calculation

WHIP (Walks and hits per inning pitched) is a stat that is not used nearly as much as ERA. It lets you know the average number of hitters that a pitcher allows to get on base per inning.

To calculate a pitchers WHIP
(Walks + Hits) / Innings pitched

In your textbook the formula for calculating WHIP would be this:
(X + Y) / Z
X = Walks
Y = Hits
Z = Innings pitched

Now onto a team statistic that people love to countdown…

Magic Number Calculation

As the season reaches about the three-quarter mark, talk about the “magic number” starts to creep into conversations (or at least sports columns). The magic number tells how many games a team needs to win or its closest competition has to lose in order to clinch first place.

To calculate the magic number:
(Total games remaining + 1) – Total number of games ahead in loss column from closest opponent.

In your text book the formula for calculating a magic number would look like this
(X + 1) – Y
X = Total games remaining
Y = Total number of games ahead in loss column from closest opponent

Now the next time you and your buddies are talking baseball statistics, you’ll be able to step up your arguments by showing how a few more hits or innings pitched can alter the stats.

One Response to Using Math to Calculate Baseball Statistics

1. CHARLY October 14, 2010 at 11:19 PM #

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