November 24, 2017

Bill James’ World Series Predictor Goes With…

October 26, 2010 by · 2 Comments 

More than 25 years ago, Bill James introduced a prediction system that picked the World Series winner with 70% accuracy. He wrote about the system for Inside Sports magazine in 1982, then expounded on it in his 1984 Baseball Abstract. He developed the system in 1972 and it accurately predicted the World Series winner at a 68% clip for 12 years. Then he went back and used it to predict all of the postseason series of the 20th century and it returned a success rate of 73%. So I’ve decided to apply the system to this year’s Fall Classic to see which team is expected to win.

The system hasn’t been updated since 1984 (as far as I know), so the point distribution may not be as precise as it should be. For example, James awards 19 points to the team that threw more shutouts during the regular season because at the time of the original research, teams with more shutouts had won 19 more postseason series than teams with fewer shutouts. There have been 38 years of postseason games since he developed the system and I have no doubt the point distribution should be adjusted based on the last four decades of playoff games, but for now we’ll stick with the old system and see how it does. Maybe someday I’ll update it and see how it works moving forward (or maybe James will).

Here’s how the system distributes points:

  • Compare the won/lost records of the two teams involved. Award one point per half-game difference to the team with the better record.
  • Give 3 points to the team that has scored more runs.
  • Give 14 points to the team that has hit fewer doubles.
  • Give 12 points to the team that has hit more triples.
  • Give 10 points to the team that has hit more home runs.
  • Give 8 points to the team with the lower team batting average.
  • Give 8 points to the team that has committed fewer errors.
  • Give 7 points to the team that has turned more double plays.
  • Give 7 points to the team whose pitchers have walked more men.
  • Give 19 points to the team that has thrown more shutouts.
  • Give 15 points to the team whose ERA is further below the league ERA.
  • Give 12 points to the team that has been in postseason play more recently. If both last appeared in postseason play in the same year, award the points to the team that was more successful at the time.

James included a 13th rule that pertained only to league or divisional playoffs and awarded 12 points based on head-to-head competition during the season. At the time he developed the system there was no inter-league play, so it wouldn’t have applied to the World Series participants since the Fall Classic would have been the first time an American League team would have played a National League team (except for the All-Star game and during Spring Training, of course).

The Rangers and Giants didn’t face each other in inter-league play this year so I’m ignoring rule 13.

Let’s see how the points are distributed between Texas and San Francisco:

  • Compare the won/lost records of the two teams involved. Award one point per half-game difference to the team with the better record.

The Giants had a regular season record of 92-70, while the Rangers posted a mark of 90-72. That’s a two-game difference, which gives San Francisco four points. They’re up 4-0.

  • Give 3 points to the team that has scored more runs.

This one wasn’t even close. Texas scored 789 runs, while San Francisco scored 697.  That’s three points for the Rangers, cutting the score to 4-3.

  • Give 14 points to the team that has hit fewer doubles.

The Rangers belted 268 two-baggers, while the Giants slapped out 284. Texas gets the 14 points and takes the lead, 17-4.

I should explain why the team with fewer doubles gets the points before I move on. James concluded that teams with more doubles are more aggressive on the base paths and that they exploited weaknesses during the regular season that won’t be present in the World Series. In fact, teams with more doubles have lost approximately 60% of the time in the postseason. So, the Rangers get 14 unanswered points and take a big lead.

  • Give 12 points to the team that has hit more triples.

The Giants had five more triples than the Rangers, lacing out 30 three-baggers to Texas’ 25. San Francisco gets the points to close the gap to 17-16. I could argue that even more aggression on the bases is needed to leg out more triples than the opposition, but I could also argue that a triple puts the runner only 90 feet from pay dirt, which makes the risk worth it.

  • Give 10 points to the team that has hit more home runs.

Well, this is awkward.  Both teams hit exactly 162 home runs, so I guess both get 10 points.  On the other hand, an argument can be made that San Francisco’s were harder to come by in a home park with a home run factor of only .885 vs. Texas’ home turf factor of 1.160.  The Giants hit more homers on the road (87) than at AT&T Park (75), while the Rangers hit far more in Arlington (93) than on the road (69).  But I don’t want to start tinkering around with another man’s formula, so both teams get 10 points, and the score is now 27-26 in favor of the Rangers.

  • Give 8 points to the team with the lower team batting average.

The Giants hit only .257 as a team while the Rangers hit. 279, so the points go to San Francisco.  Texas’ average is inflated by Rangers Ballpark, which boasts the fourth best hits factor (1.066) in all of baseball, while San Francisco’s is hurt by AT&T Park, which ranks 21st at .969. And an explanation is in order as to why the team with the lower AVG gets the edge. “Why do teams with high batting averages do poorly in World Series play?” asked James. “A simple reason: it takes them too many hits to score.”  The Giants aren’t exactly a Punch-and-Judy club, ranking sixth in the N.L. in slugging, and neither is Texas, who also ranked sixth in SLG.  The Giants get the eight points and take back the lead, 34-27.

  • Give 8 points to the team that has committed fewer errors.

No explanation needed here. Only the Padres and Reds committed fewer errors in baseball (72) than the Giants, who made only 73 miscues and led all of baseball in defensive efficiency at .706.  Meanwhile the Rangers posted a very good defensive efficiency score of .701, but committed 105 errors, 32 more than the Giants.  San Francisco gets the points and pushes its advantage to 42-27.

  • Give 7 points to the team that has turned more double plays.

Texas turned 132 DPs, while San Francisco turned only 110, the fewest in the majors. Of course part of that is a product of fewer base runners.  San Francisco’s pitchers held opposing batters to a .313 on-base percentage and led the bigs in strikeouts with 1,331, but that’s neither here nor there. The Rangers get the points and pull to within eight at 42-34.

  • Give 7 points to the team whose pitchers have walked more men.

San Francisco’s staff walked 578 batters during the season, while Texas’ issued free passes to 551. Seven more points go to the Giants to give them a 49-34 lead.

To be honest, I’m not quite sure why the team with more walks gets the points here and James doesn’t really explain it. He attributes a lot of the walks to the starters at the back end of the rotation, but admits that those hurlers will have little impact on the outcome of the World Series. I suppose that more walks means fewer chances to get a hit that might plate a run or an extra-base hit that might plate multiple runs while putting runners in scoring position. Either way, the Giants get seven more points.

  • Give 19 points to the team that has thrown more shutouts.

The Giants tossed more than twice as many shutouts (17) as the Rangers (8) and earn a whopping 19 points to double up Texas, 68-34.

  • Give 15 points to the team whose ERA is further below the league ERA.

San Francisco’s ERA of 3.36 was 0.66 below the N.L. average of 4.02. Texas’ 3.93 mark is only 0.21 points lower than the A.L. average. The Giants have cruised to a big lead at 83-34 with only one category to go.

  • Give 12 points to the team that has been in postseason play more recently. If both last appeared in postseason play in the same year, award the points to the team that was more successful at the time.

Texas’ last postseason appearance came in 1999 when they won a division title before losing to the Yankees in the ALDS. The Giants won a division title in 2003 but lost to the wild card Florida Marlins in the NLDS, and were in the 2002 Fall Classic. San Francisco gets another 12 points to make this an unmitigated blowout at 95-34.

If the Series follows the point distribution pattern, the city of San Francisco will finally have its first World Series title and the Rangers will have to “wait till next year” (again).  But the games aren’t played on paper, as they say, so we’ll see how this unfolds in the coming days.  No matter how you slice it, this has been a memorable and exciting postseason so far.

Category (points) Edge SFG Pts. TEX Pts.
Won/Lost Record (1 per 1/2 game) 92-70 90-72 4 0
More Runs (3) 697 787 0 3
Fewer Doubles (14) 284 268 0 14
More Triples (12) 30 25 12 0
More Home Runs (10) 162 162 10 10
Lower Batting Average (8) .257 .276 8 0
Fewer Errors (8) 73 105 8 0
More Double Plays (7) 110 132 0 7
More Walks Issued (7) 578 551 7 0
More Shutouts (19) 17 8 19 0
ERA Lower than LG (15) 0.66 0.21 15 0
More Recent Postseason (12) 2003 1999 12 0
2010 World Series Champion 95 34

This graphic was designed by Lorena O’Neal, you can check out more of her work here.

Source: www.sportsmanagementcolleges.net

Sports Management Colleges- MLB Postseason

Mike Lynch is the author of Harry Frazee, Ban Johnson and the Feud That Nearly Destroyed the American League and It Ain’t So: A Might-Have-Been History of the White Sox in 1919 and Beyond, and the founder of Seamheads.com.

Comments

2 Responses to “Bill James’ World Series Predictor Goes With…”
  1. Devon Young says:

    This is interesting. Have you done this for the past 25 years of World Series? Or do you know where I can find a listing of this for each year?

  2. Mike Lynch says:

    Originally Posted By Devon Young
    This is interesting. Have you done this for the past 25 years of World Series? Or do you know where I can find a listing of this for each year?

    I haven’t done this for the past 25 years of World Series, but it would be a fun project to do. I’m finishing up a seven-part series of articles that I hope to have done soon. After that, I’ll put something together for you (and the site).

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