How Important Is Team Defense in Winning World Series Championships?

True or false: Defense wins championships.

Sure, it's a fun little phrase, but does that axiom serve as more than simply a way for managers and coaches to get players to practice and concentrate on what is often considered the less-exciting aspect of baseball?

After all, what would you rather watch: A 500-foot home run or a routine 6-4-3 double play?

Perusing the past 10 seasons showed that while chicks may dig the long ball, leather really deserves lots of love, too.

In recent years, there has been a significant movement in baseball to better understand defense via various defensive statistics and metrics.

The game has moved well beyond more basic figures like errors and range factor, which were once not only common, but also among the only ways to measure defense. Today, though, you can check a site like FanGraphs or Baseball Reference and find more comprehensive metrics like Ultimate Zone Rating (UZR) and Defensive WAR.

As fantastic as those stats are, they're often used more for individual players. Defensive Efficiency from Baseball Prospectus, on the other hand, is effective for measuring on a team-wide scale. Plus, unlike some other defensive stats, it's fairly easy to understand: Defensive Efficiency measures the rate at which balls put into play are converted into outs by a team's defense.

For frame of reference, there's not much variation in the Defensive Efficiency numbers posted by the very best teams and the very worst. For instance, in 2012 the Angels led baseball with a 0.723, meaning they converted over 72 percent of balls in play into outs; whereas the Rockies came in last at 0.675, meaning they managed to successfully turn a ball in play into an out less than 68 percent of the time.

A four percent swing might not seem like a whole lot, but when you stop to think about the thousands of balls put into play against any given team, well, it adds up. Quick.

Since we're looking to show what sort of role defense has when it comes to success on the field, we'll go with Defensive Efficiency to take into account team performance as a whole.

Consider...

From 2003 through 2012, an average of 3.8 teams—basically, four per year—that placed in the top 10 in defensive efficiency earned postseason berths. In other words, out of a total of 82 postseason berths in the past 10 years (eight per season from 2003-11 and 10 in 2012), 38 went to teams who were in the top 10 in defensive efficiency that season—or 46 percent.

Here's a table of the teams that did this each season.

NOTE: Italics indicate a World Series appearance and an underline signifies a World Series win that season. The number in parentheses is the team's ranking in defensive efficiency that year.

YEAR	#	POSTSEASON TEAMS IN TOP 10 DEF EFFICIENCY
2012	4	Athletics (3), Nationals (5), Braves (7), Orioles (9)
2011	3	Rays (1), Rangers (2), Phillies (10)
2010	6	Rays (2), Rangers (4), Yankees (5), Giants (6), Reds (9), Phillies (10)
2009	3	Dodgers (2), Yankees (8), Cardinals (9)
2008	5	Rays (1), Cubs (2), Brewers (4), Red Sox (6), Phillies (9)
2007	3	Cubs (1), Red Sox (3), Rockies (8)
2006	5	Padres (1), Mets (2), Tigers (3), Cardinals (7), Yankees (8)
2005	3	White Sox (2), Astros (4), Cardinals (5)
2004	3	Cardinals (1), Dodgers (2), Red Sox (10)
2003	3	Athletics (2), Giants (4), Braves (9)

So while a strong defense wasn't a necessity to make the postseason, having a group of good gloves obviously helped teams get to October.

Once there? Well, that's where the webs became the real gems.

There are three noteworthy interpretations to glean from the chart above, each one more poignant than the last:

1. Over the past 10 seasons, 14 of a possible 20 teams who made the World Series were in the top 10 of defensive efficiency in that season. That's 70 percent, if you're scoring at home.

2. Between 2004 and 2008, which encompassed five consecutive World Series, all 10 teams to make it to the Fall Classic were in the top 10 in defensive efficiency. Think about that for a second.

3. From 2004 through 2010—that's seven straight seasons!—every single World Series winner was ranked in the top 10 in defensive efficiency

Obviously, there are exceptions. Just last year, the Giants and Tigers were the last two teams standing, and they ranked 13th and 27th in Defensive Efficiency, respectively.

But to find the previous time that both clubs in the World Series were outside the top 10, you'd have to go back to 2003, when the Marlins (23rd) beat the Yankees (28th).

The point? Even when the D wasn't that good, the better gloves got the ring.