Home, run! History in the Making at Chase Field

Fun facts are a bit of a misnomer. For anyone who listens to the Effectively Wild podcast produced by Baseball Prospectus – really, you all should – this claim isn’t anything new. At their core, fun facts massage and knead history until some nugget is left that usually tricks the masses into thinking they’ve seen something special.

To start, an example: The 2016 Diamondbacks have the fifth worst home ERA ever for an NL team during the fourth through sixth innings. This is inarguably a terrible fun-fact because there’s nothing special about the defined range of innings to bestow any historical importance to the team’s awfulness, not to mention the team isn’t even the worst ever in this arbitrary range. Possibly even more egregious is the reality that this fun fact undersells just how terrible the Diamondbacks have been at home.

Enter, records. Though seldom realized as being a sub-class of fun facts, records are simply fun facts that are actually a bit more truthful but less fun. They don’t seek to hide larger outliers to feign the appearance of being the biggest outlier. Yes, the Diamondbacks have waved traditional fun facts goodbye and are entering into the realm of records. Though they’re not the outright worst home team of all-time, or even the worst this year thanks to the Braves, fear not, they’re in the process of entering into their own place in history.

It’s pretty common for teams to be better on the road than they are at home. As far back as the Baseball Reference Play Index goes for team records, 1901, there have been 2452 seasons of baseball played. In a little over 83% of those, teams had a better record at home than they did on the road. Each season, it’s fair to expect that there will be about five teams that somehow end up with a better winning percentage on the road. So far in 2016, there have been five teams that fit this criterion: Tampa Bay, Oakland, Atlanta, St. Louis, and Arizona. Somehow, the team with the best fans in baseball finds itself playing quite terribly in front of these celestial spectators, relative to how they play elsewhere.

All digs at Cardinals fans aside, there are probably perfectly reasonable answers as to why these teams are all so bad at home, aside from the banal attribution of randomness – which usually seems to be the actual answer. Chase Field in particular is subject to unique conditions and perhaps several of the players on the team do not fit well into what the park demands. For Arizona’s part, there is some historical significance at play.

The Diamondbacks have a .327 winning percentage at home and one of .535 on the road for a difference of -.208. That is not only the worst gap between home and road winning percentage this year, but it would be the worst gap in MLB history. What’s more, the Diamondbacks are on pace to be the worst home team in baseball history, relative to their performance on the road.

The historical record skews towards teams being better at home and there are actually 154 teams who have essentially been the Arizona’s opposite. That is, 154 teams in baseball history have had a home and road winning percentage differential of .208 or higher. However, it is relatively unprecedented for a team to be this bad at home and this good on the road. The 1994 Cubs are the only other team in the same ballpark as the Diamondbacks here. That Cubs team was 20-39 at home and 29-25 on the road for a winning percentage differential of -.198. Conceivably, they could have regressed both records towards their true talent level had the season not been shortened by the strike, and the Diamondbacks could very well see their home and road records regress towards each other as the rest of this season plays out.

To read into things for a second, perhaps in some ways this exonerates the front office – they built a team that, anywhere else, seems to be a decent baseball team. Since Dave Stewart assumed the position of GM, the Diamondbacks are a better than .500 team on the road. It wouldn’t be unreasonable to suggest that Stewart and Tony La Russa have had a keener eye for talent than they are given credit for. It may not excuse their lackluster appraisal of how to find a player’s market value and the bevy of questionable trades that have followed, but at least they’re building a team that has been competitive in 29 other parks.

At the same time, it brings up a new criticism: Does the front office understand what type of players are helped and hurt by Chase Field’s park factors? The team is now more than 20 games under .500 at home in the two seasons that this new front office has been in place. Again, though, they’ve been a competent team on the road.

Maybe it’s just randomness. In the 2452 seasons that have been played in recorded baseball history, it would probably be more surprising than not for there not to be a season somewhere along the line like the one the Diamondbacks are having this year. Given enough chances, anything that can happen will happen. It’s certainly plausible this season is just turning into a fun fact by the whims of chance. Nonetheless, the question is worth pondering: Does this front office understand Chase Field?