Monday, October 12, 2009

Saber Correct Tigers, Efficient Athletics

Many fans complained that the Tigers left too many runners on base and did not get the most out of their offense this year. Some said the same thing about the 20o7 and 2008 teams. In actuality, the Tigers scored almost exactly as many runs as they should have given their totals of hits, walks and various other positive batting events in both 2007 and 2008. Today, we'll take a look at 2009.

The Tigers finished tenth in the league with 743 runs scored in 2009.
Should they have gotten more runs from their offensive output? One way to answer this question is to look at weighted runs created (wRC). wRC is calculated from the number of walks, singles, doubles, triples, home runs and other things that a team does to score runs. The formula for wRC is a bit involved but the idea is that different batting events are given different weights according to how much they contribute to runs scored:

BB 0.31
HBP 0.34
1B 0.47
2B 0.77
3B 1.04
HR 1.40
SB 0.20
CS -0.42

From examination of thousands of games, it has been determined that, on average, a single contributes 0.47 runs. That is, if you add one single to a team's hit total in each game for 100 games, you can expect that to add 47 runs to their season total. The values for the other events can be interpreted similarly.

Applying the above weights to a full season of plate appearances yields a team's wRC. Table 1 lists the runs, wRC, difference between runs and wRC and % difference for all American League teams in 2009. Table 2 does the same for National League teams. The first thing you should notice is that all but 3 teams in the majors had wRC estimates within 5% of their actual runs scored. This means that wRC gives a good estimation of runs scored in most cases.

A closer look at table 1 shows that the Tigers had 739 runs created in 2008. So, their 743 runs scored was almost exactly as many runs many runs as would have been expected given their offensive output. That tells us that the Tigers were neither efficient nor inefficient with their offense. They were an average team in terms of making the most of their base runners.

The American League team which got the biggest bang out of their offensive output was the Oakland Athletics. Yes, Billy Beane's collection of softball players who clog the bases and don't play the game the right way had the most efficient offense in the majors. The Athletics scored 50 more runs than their runs created estimate. One reason for this was that they were the best base running team in the Majors according to the Equivalent Base Running (EqBRR) statistic at Baseball Prospectus (Base running skill beyond SB/CS is omitted from wRC). Based on EqBRR, the Athletics created 12.5 more runs with their base running than the average team.

The least efficient AL team might also surprise some people. The New York Yankees led the Majors in runs scored with 915 but should have created 971 according to their wRC. One reason for the discrepancy is that the Yankees did not hit as well with runners in scoring position (.766 OPS) as they did with the bases empty (.854 OPS).

Table 1: Efficiency of American League Offenses in 2009

Team

Runs

Runs Created

difference

% difference

Athletics

759

708

51

7.2

Angels

883

843

40

4.7

Rangers

784

758

26

3.4

Royals

686

677

9

1.3

Twins

817

807

10

1.2

White Sox

724

718

6

0.8

Tigers

743

739

4

0.5

Orioles

741

738

3

0.4

Indians

773

780

-7

-0.9

Blue Jays

798

807

-9

-1.1

Red Sox

872

882

-10

-1.1

Mariners

640

651

-11

-1.7

Rays

803

821

-18

-2.2

Yankees

915

971

-56

-5.8


Table 2: Efficiency of National League Offenses in 2009

Team

Runs

Runs Created

difference

% difference

Giants

657

607

50

8.2

Reds

673

659

14

2.1

Cardinals

730

719

11

1.5

Pirates

636

633

3

0.5

Marlins

772

769

3

0.4

Dodgers

780

779

1

0.1

Phillies

820

821

-1

-0.1

Brewers

785

786

-1

-0.1

Rockies

804

807

-3

-0.4

Diamondbacks

720

724

-4

-0.6

Padres

638

642

-4

-0.6

Braves

735

746

-11

-1.5

Cubs

707

719

-12

-1.7

Astros

643

655

-12

-1.8

Nationals

710

737

-27

-3.7

Mets

671

698

-27

-3.9

2 comments:

  1. Is there an easy way to split this up by month or by half seasons? I feel like the Tigers were just lucky in the first half on offense and were bit by variance in the second half.

    ReplyDelete
  2. Shorts, here are the Runs and wRC numbers for April-Jun and Jul-Oct

    April-June 368 348 +20
    July-Oct 375 391 -16

    You are right that they were more efficient in the first half than the second half. Note that the runs are still within 5% of the wRC when looking at halves though.

    Lee

    ReplyDelete

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