Fun With Pythagoras, pt. 5

added 5/26/2005 by Scott Barzilla

Columnist Note: This is our last edition with hardcore numbers. It also is going to be the most difficult edition. In this edition, we look at the affects of defense on the Pythagorean ratings.

Those that know me well know that I have been a skeptic of defense for a long time. Yet, it isn’t defense that I’m skeptical of, it is the numbers used to determine value that make me skeptical. As usual, I need to back up a bit a little bit and explain what I am talking about.

Those of us in the statistical community like the break down the whole to a collection of parts. That means that the sum of the parts is equal the whole. Those that know more about math than I call these derivatives. To the math challenged like myself I will simply say offense is fairly easy to analyze because the numbers are easier to individualize. Therefore, you can interchange parts and predict the future with some accuracy.

Defense is much more difficult to analyze because players have symbiotic relationships with each other and the pitcher. For instance, a shortstop with great range can rob balls away from the third baseman or second basemen. A great centerfielder can do the same to the corner outfielders. After considering this we have to consider how pitchers affect all fielders. Power pitchers remove fielding opportunities from all fielders while others surrender more fly balls or groundballs.

Defensive metrics have evolved a great deal over the years. It started off with fielding percentage and errors in the early years, but these numbers are very deceptive. After all, if you go according to fielding percentage then Darryle Ward would make a great left fielder. One cannot commit errors if one cannot get to the ball. So, this evolved into calculating the number of plays a player makes. This was better than fielding percentage, but still fell prey to the pitfalls from above.

Today, companies like STATS Inc use metrics like zone rating. They calculate the percentage of balls a fielder fields that are hit into his zone. This removes much of the biases that other fielders and pitchers put in the fielding process. However, it still has some bias because this still subjectivity in the process. Someone has to decide which zones belong to what position. Obviously, as we have seen this season, there are many plays that occur between fielders. Even though zone rating is an improvement, it is still subject to the same biases as the conventional methodology.

So, what are we left with? We are left with eyewitness accounts. This is where me and my buddy Willie Lakey always disagree. I don’t trust that which can’t be quantified while Willie likes to go by eyewitness accounts. If you think I’m wrong then ask yourself whether Derek Jeter really is the best defensive shortstop in the American League. We always agree to disagree on some things and this will just have to be one of them.

This diatribe has a point and the point is this. No one can deny the value of defense, but determining that value on an individual basis is nearly impossible with the present data. We can look at team defensive data with a great deal of confidence. We will look at two such numbers. The first is a statistic from baseball prospectus.com called runs on errors (ROE). We will compare those numbers with the league average as we have with most of the other numbers. We will do the same with baseball prospectus defensive efficiency.


                       ROE    LG AVG     Ratio
Atlanta Braves         733       644        86
Boston Red Sox         741       616        80	
Cleveland Indians      608       616       101
Houston Astros         711       644        90	
New York Yankees       636       616        97	
St. Louis Cardinals    715       644        89

The ratio numbers were reversed again for effect. The Astros finish in the middle of the pack on these numbers, but none of them are something you should write home about. They are pretty easy to explain when we consider that all of these teams had good offenses throughout the decade. Good offensive players (particularly those with power) don’t tend to be quick.

So, we are in the unenviable position of choosing between looking at the Astros third place ranking in the category or the fact that they are ten percent below the league average. When we consider all of the other categories where the Astros were below average we can see which side we should fall on. However, it’s not as simple as getting better fielders. You also need pitchers that can overcome the errors. Not coincidentally, the Astros worst season in this regard was in 2000 when they had their worst season for pitching. Perhaps the defensive efficiency rating will be more enlightening.


           Def Eff.     LG AVG      Ratio
Braves        .6987      .6926      100.8
Red Sox       .6896      .6896      100.0	
Indians       .6860      .6896       99.4
Astros        .6858      .6926       99.0
Yankees       .6921      .6896      100.3	
Cardinals     .6989      .6926      100.9

I know what most of you are thinking because I was thinking it to. You’re thinking that these numbers are virtually meaningless. After all, less than two percent separates the top team from the bottom team. I was inclined to agree until I stopped and thought about it. Do you realize how many balls are put in play in play on a nightly basis? If we assume that a team averages six strikeouts per nine innings then the team has to record 21 outs to finish the game.

This is where I have to recall my high school algebra and use an equation. If we multiply 30 times .6926 we get 20.778. That means that the league average team surrenders 9.222 hits per game. Now, take the Astros mark of .6858 and do the same multiplier and you get 20.574 or 9.436 hits per game using the same number of strikeouts. Multiply the difference (.196) times 162 games and you see that the Astros surrendered an average of nearly 32 extra base runners a season. How many of those are home runs, doubles, or triples.

The difference between the best and worst team in the National League in 2004 was .03 . That means that there are less than 50 hits separating the top two teams. So, maybe it is much ado about nothing, but in terms of one run games it could make a profound difference.

Of course, we could go round and round on defense, but I’m afraid I’d get dizzy and have to lie down. The point is that the other teams got to more balls than the Astros the last ten years. The Astros did a better job catching the ball than half of the teams on the list, but when you get to fewer balls it is easier to catch a higher percentage of them. Overall, we cannot say that the Astros were even an average defensive club over the course of the decade.

Currently, a more impressive crop of fielders are coming through the system. At present, Chris Burke and Willy Taveras look to be solid defenders at their position. They will accompany Adam Everett and Morgan Ensberg to give the club several solid defensive players. 2005 fluctuate of course, but throughout most of the season they have been above average in terms of defensive efficiency. It will only get better when all of those players get into the lineup and get accustomed to their position.

Coming Up Next

We have finished looking at all of the hardcore numbers. Next time we’ll look everything from a couple of giant steps back. After all, numbers are impressive, but if you can’t use them to reach understandable conclusions then they are meaningless. We’ll try to come up some answers based on what we have seen.

Scott Barzilla is the author of “Checks and Imbalances” and “The State of Baseball Management”