Baseball::Sabermetrics - A Baseball Statistics Module


Baseball::Sabermetrics provides an easy interface for calculating baseball statistics, given a data importer. In this package, I've written for (Chinese Professional Baseball League,

  use Baseball::Sabermetrics;
  use Baseball::Sabermetrics::CPBL;

  my $league = Baseball::Sabermetrics->new(league => 'CPBL');

  # Actually these are predefined.
  # Those data with 'p_' or '_allowed' here are for seperating pitchers
  # and batters.

      rc => 'ab * obp',
      babip => '(h_allowed - hr_allowed) / (p_pa - h_allowed - p_so - p_bb - hr_allowed',
      # what started with '$' will be reserved.
      # Players have team and league predefined, and team has league.
      formula1 => 'hr / $_->team->hr';
      formula2 => 'hr / $_->league->hr';
      complex => sub {
            print "You can write a sub directly\n";
            $_->slg - $_->ba;

  # Some formulas can be applied to players, teams, and league, depend on what
  # columns are used in the formula.  For example, ab and obp are defined for
  # players, teams, and league, so that rc is available for all of them.

  # top 5 obp of teams
  $_->print qw/ team name ba obp slg isop / for $league->top('teams', 5, 'obp');

  # top 10 obp of players
  $_->print qw/ team name ba obp slg isop / for $league->top('players', 10, 'obp');

  # show a player's information
  $league->players('Chien-Ming Wang')->print qw/ win lose ip so bb whip go_ao /;
  $league->teams('Yankees')->players('Chien-Ming Wang')->print qw/ win lose ip so bb whip go_ao /;

  # show team statistics data (accumulated from players')
  $league->{Yankees}->print qw/ win lose ip so bb whip go_ao /;

  # give a brief report for pitchers/batters of the team
  $league->{Yankees}->report_pitchers qw/ name ip p_so p_bb whip go_ab /;
  $league->{Yankees}->report_batters  qw/ name ba obp slg isop /;

  $league->report_teams qw/ name win lose era obp /;

  # show all available formula
  print join ' ', $league->formula_list;

Data Structure

Baseball::Sabermetrics is aimed for providing a base class of your interested teams (a league, for example). You'll need to provide a data retriever to pull data out. The following example shows how you have to fill data into this structure.

 $league = {
    teams => {
        Yankees => {
            players => {
                "Chien-Ming Wang" => {
                    bio => {
                        bats => 'right', # coule be left, switch
                        throws => 'right',
                    ip => 57.33333333333,
                    game => 9,
                    fielding => {
                        p => {
                            tc => 43,
                            pop => 4,
                        # b1 => { }, b2 => { }, b3 => { },
                        # first, second and thrid baseman should be
                        # b1, b2, and b3 respectively for convenient in
                        # fielding context.  Because the initial of the
                        # name of subroutine can't be a number in perl.
        Athletics => {


Available terms of players (including teams and league, which are accumulated from players and could be treated as an abstract player) are:

    # pitching
    p_game win lose tie gs sv bs hld cg sho ip p_pa np h_allowed
    hr_allowed sh_allowed sf_allowed p_bb p_ibb hb p_so wp bk ra er

    # batting
    pa ab rbi r h 1b 2b 3b hr tb dp sh sf ibb bb hbp so sb cs
    tc po a e f_dp ppo tp pb c_cs c_sb

    # fielding
    pos fgame tc po a e f_dp tp pb c_cs c_sb

And there are additional terms for team:

    game win lose tie



Create sabermetric data set of a group of teams. The following keys are supported:

    league: a string like 'CPBL', which is a module and has to be defined in Baseball::Sabermetrics::League::CPBL.

    data: If your league is not exists there, you can feed in a structure mentioned above.

    Accumulate: If $hash{Accumulate} is false, players data will not be accumulated to their teams and the league (and therefore team-wise and league-wise statistics are not allowed). Default is to accumulate stats.

    for ($league->players) { ... }
    # or specify the name for the player
    print $league->players('Someone')->obp;
    for ($league->teams) { ... }
    # or specify the name for the team
    print $league->teams('Someone')->win;

Return all pitchers, i.e., NP (Number of Pitches) > 0.


Return all batters, i.e., PA (Plate Appearances) > 0.


Victor Hsieh, <victor at>


Please report any bugs or feature requests to bug-sabermetrics at, or through the web interface at I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.


You can find documentation for this module with the perldoc command.

    perldoc Baseball::Sabermetrics

You can also look for information at:


Copyright 2006 Victor Hsieh, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.