Last night baseball saw not one, not two, not three, but four grand slams. Whilst Fernando Tatis’ and Alfonso Soriano’s were the ones that put their games beyond doubt, what grabbed my attention was the two in back-to-back innings by Washington’s Josh Willingham.
This was particularly brilliant for me, not just because I’ve always kind of liked the Nats, but because I’ve long argued that whilst Washington undoubtedly are terrible (31-68) they have some brilliant hitters that are really fun to watch. After last night the top six of Washington’s order runs like this:

Nyjer Morgan CF .303/.366/.380
Cristian Guzman SS .299/.314/.403
Ryan Zimmerman 3B .284/.349/.483
Adam Dunn LF .278/.405/.554
Nick Johnson 1B .295/.407/.405
Josh Willingham RF.298/.410/.596

Compare this to, say, the top 6 in the New York Yankees batting order:

Derek Jeter SS .325/.402/.459
Johnny Damon LF .278/.364/.504
Mark Teixeira 1B .282/.379/.551
Alex Rodriguez 3B .248/.392/.525
Hideki Matsui DH .252/.358/.485
Jorge Posada C .285/.367/.522

What surprise me is the difference in batting averages between the two. New York sports some good AVGs and some surprisingly low ones. Washington, on the other hand, all sit closer to or above the .300 mark. The Yankees certainly have more power across the board, but could this be due to the fact they play in the home run paradise that is Yankee stadium? The Nats seem to have some impressive OBP numbers with Dunn, Johnson and Willingham being particularly adept at getting on base.
To contrast the power in these two lineups we can look at each hitter’s Isolated Power (ISO) which (to quote Baseball Prospectus) “measures a hitter’s raw power in terms of extra bases per at bat” the formula they use is ISO = (2B + (3B*2) + (HR*3)) / AB
giving greater value to triples than doubles and home runs over them both, obviously. Here’s the lineups using just the power stat:

Washington:
Morgan .077
Guzman .104
Zimmerman .199
Dunn .275
Johnson .110
Willingham .298

New York:
Jeter .134
Damon .226
Teixeira .269
Rodriguez .277
Matsui .233
Posada .237

The stat illustrates the power in the Yankees lineup and the lack of pop in the Nats’ bats, Dunn and Willingham aside. Could the problem be, again, the ballpark that the Yankees play in? To eliminate this we can look at a player’s equivalent average (EqA), a sabermetric stat that measures a player’s “total offensive value per out”, the EqA is deliberately designed to be approximate to a batting average (eg. 260 is about league average .300+ is very good). The good thing about this stat is that the numbers are normalized to eliminate factors such as the ballpark players are playing in and the the differences of playing in the American League over the National League, putting all these stats in a ‘neutral arena’ regardless of whether the player plays mostly in a hitter’s or pitcher’s ballpark. Let’s look at the how the two teams measure up in terms of EqA:

Washington
Morgan .312
Guzman .247
Zimmerman .287
Dunn .323
Johnson .294
Willingham .337

New York
Jeter .302
Damon .298
Teixeira .309
Rodriguez .310
Matsui  .288
Posada .300

Most striking, when viewed in that way, is the consistency that can be found amongst the top of the Yankee’s batting order which isn’t really reflected in their actual batting averages. The EqA numbers show what we might have suspected, that the Yankees power numbers aren’t high because of the ballpark they play in, it’s because they’re just good baseball players. Washington, on the other hand, benefit from the ability of Morgan, Guzman and Zimmerman to hit and get on base, with the power bats of Dunn, Johnson and Willingham (in theory) driving them home. Dunn and Johnson’s high EqA may be helped in part by their excellent batting eyes and the amount of walks both can take, as well as hitting the ball over the fence.

Looking at the numbers in three different ways is, as always, more fun than anything. I’m not trying to say that the Nationals are better than the Yankees, they’re clearly not. What is interesting, though, is the variety of ways that the Nats batting order can help them – Morgan and Guzman are at the top of the order for their speed and hitting, the rest of the bats in the top 6 can kill a pitcher on any given day, as they showed in Millwauke last night. Perhaps the Yankees are the better team (infinitely better pitching aside) because they are the most consistent in their numbers but, with the trade deadline approaching I’d wager that any of Dunn, Johnson and Willingham could be a massive asset for a team looking to increase it’s power output. Dunn’s low career batting average may be off-putting to some but the amount of walks he takes and the fact he’s well on his way to his sixth straight 40+ home run season cannot be overlooked. 
 
I must credit baseballprospectus.com and baseball-reference.com here, who’s stats I’ve used in this post.