A baseball team can’t win if it doesn’t score runs, and the fastest way to do that is to hit the ball over the fence. It’s no surprise that teams that hit more home runs tend to win more often, but the relationship between rostering a world-class power hitter and team performance is less clear. Below, in a plot of team seasons since 1950, we see a fairly clear positive relationship between the number of teams a home run hits and how well they do during the season: as one rises, so does the other. If you’re interested in Pythagorean winning percentage, the correlation is roughly the same.

Talk Chris Davis contracts, the Orioles’ home run dependency, and this article on the BSL Forums.

Team Home Runs and Winning Percentage Since 1950

And if you’re wondering why the cutoff was 1950, it’s because 650 of the 961 team seasons on record before that year featured fewer than 100 home runs, while winning percentages were much more spread out than they are now. The game of yesteryear is different than it is today in that there was far less parity and no focus whatsoever on power hitting. Ignoring those seasons gives a look at the modern game and includes only relevant information.

When Chris Davis becoming the first Oriole to post two 40-home-run seasons, I wondered whether having a single world-class hitter, who would inevitably be responsible for a good chunk of the team’s home run total, would be a benefit. Not surprisingly, teams with a stud power hitter are better than .500 more often than not – but having a slugger in the lineup is certainly no guarantee that the team will be good.

40+ home run hitter and winning percentage frequency

In fact, the farther a player goes over 40 home runs, the worse his team tends to do, albeit only barely. And anyway, it’s likely as a result of a small sample size. With few teams featuring hitters reaching the highest numbers in the home run record books, one bad team can pull the relationship downward. The 1999 Cubs, for instance, got 63 home runs from Sammy Sosa and finished 67-95. This could be a complete coincidence due to small sample size, and I’d attribute most of it to exactly that, but it’s worth noting that a monster slugger can eat up a lot of a team’s budget if he’s signed in free agency. Devoting all of those resources to one bat has to have an adverse affect on a team’s ability to build around him, but the effect is probably not as detrimental as it appears here.

Linear Relationship Home Runs and Win Percentage

But my real surprise came when I pointed out the Orioles seasons since 1954 in which the team featured a 40+ home run hitter. Actual winning percentage is shown on the left, and Pythagorean winning percentage, or likely winning percentage based on run differential, is shown on the left. The 2015 Orioles, with free-agent-to-be Chris Davis, are the lowest-performing Oriole team to have a 40+ home run hitter in the lineup. Ever. The team’s run differential is good for a .519 Pythagorean winning percentage, enough to move them just barely ahead of the 1998 Orioles, when Rafael Palmeiro hit 43 round-trippers en route to a 79-83 finish and a Pythagorean winning percentage of .518. Of course, that can change with a few tough games as the 2015 squad closes out the season.

1950_player hr and both win pct

Patrick Dougherty
Patrick Dougherty

Patrick was the co-founder of Observational Studies, a blog which focused on the analysis and economics of professional sports. The native of Carroll County graduated with a Bachelor’s degree in Economics from Loyola University Maryland. Patrick works at a regional economic development and marketing firm in Baltimore, and in his free time plays lacrosse.