It’s not as if the Red Sox haven’t had their disappointments. Critics warned that J.D. Drew was overpriced and under-motivated. So far, they’ve been right. Drew has been better than Bobby Abreu, but not by much, and he batted .171 in May. The critics also said that Julio Lugo was a mediocre hitter and fielder who folded in the glare of the pennant race last season. They were correct: Lugo’s on-base percentage is .291 (.241 in May), but manager Terry Francona hasn’t noticed, keeping him in the leadoff spot for much of the season.

The litany of failures goes on. They said Coco Crisp wouldn’t hit, and that once Jon Papelbon went back to the bullpen, the Red Sox would have to do without a fifth starter. Julian Tavarez has been better than could have been expected, but still not very good. Although it was not predicted, the inconsistency of Daisuke Matsuzaka has proved equally true. Matsuzaka has a winning record, with an ERA approaching 5.00, but he hasn’t been one of the 50 best starting pitchers in the game.

Compare that with what the Yankees have suffered. The aforementioned Abreu has been lost at sea. Until recently, Robinson Cano has been a disaster — even his late-May hot streak didn’t get his rates for the month above .260 AVG/.278 OBA/.442. SLG. Johnny Damon, his odometer rolling over, has been no better than mediocre at the plate and in the field. Back in spring training everyone fretted over how much playing time Melky Cabrera would get this season. As things turned out, he got a lot of playing time, every plate appearance of it too much. Now with Jason Giambi now going down for an extended spell, Cabrera is assured even more playing time. (Joe Torre has a hard time writing “Josh Phelps” on his lineup card.) And of course Doug Mientkiewicz has been exactly what everyone except Torre and Brian Cashman expected him to be. Even during his May surge, Mientkiewicz batted only .265/.320/.441, which does not qualify in 2007 as an average performance for a first baseman.

Still, each team has had hitters live up to or exceed expectations: Derek Jeter, Alex Rodriguez, and Jorge Posada for the Yankees, and Kevin Youkilis, Mike Lowell, and David Ortiz for the Red Sox. Each club has also had some hitting successes in a lower key. Jason Varitek seemed to carry his poor 2006 record into this season but shook off the rust in May; Dustin Pedroia seemed to be on the verge of losing the second base job to Alex Cora when he got hot, batting .415 in May. On the Yankees side, Jason Giambi still excelled at getting on base, even when injured, and Hideki Matsui has hit well since coming off the disabled list.

When the various plusses and minuses are added up, the results of the two club’s offenses have been markedly similar. The Yankees are hitting .272/.349/.426. The Red Sox are hitting .277/.359/.447. When you shake out the differences in home parks, Boston’s edge all but disappears.

The difference, then, comes down to pitching. The Red Sox have gotten a 3.98 ERA from their starters, the Yankees 4.71. The Boston bullpen has been shockingly good, with Hideki Okajima, and Papelbon giving the Sox a great one-two punch at the end of games. The Yankees don’t have anything like that, though it should be noted that the deficiency is partially by choice — Joe Torre has been slow to use his weapons to best advantage. The hard-throwing, easy-losing Kyle Farnsworth has been used in more pressure situations than any Yankees reliever despite his lack of success in those situations. Brian Bruney, the team’s most effective reliever to date, has generally been used in lower-leverage situations.

Boston’s starters haven’t been perfect, but general manager Theo Epstein and his pals chose wisely when they bet on durability. Aside from Josh Beckett’s brief stint on the disabled list, the Sox starters haven’t missed any time. Conversely, Yankees starters have been spotted in doctor’s offices nationwide. With the exception of Andy Pettitte, every starter has missed time. Cashman gambled on getting value out of Carl Pavano and lost. Kei Igawa has been Japan’s answer to Ed Whitson. In the pen, Kyle Farnsworth was not good last year, while Scott Proctor was overworked. Cashman acquired two supplements in Luis Vizcaino, a disaster, and Chris Britton, who has been exiled to Scranton.

Even if Boston plays .500 baseball from now on, they’d almost certainly make the postseason. The team hasn’t been lucky, and it hasn’t been perfectly good, but the values the Sox embraced in building the team were just a little more focused than those of the Yankees, who seemed to say, “It will work out. It always has.” Instead, they were unfocused and unlucky, leaving them to play Boston this weekend with very little on the line except salvaging a bit of dignity.

Mr. Goldman writes the Pinstriped Bible for yesnetwork.com and is the author of “Forging Genius,” a biography of Casey Stengel.