Interleague Attendance Boost Mostly a Mirage

This article was written by Pete Palmer - Gary Gillette

This article was published in 2006 Baseball Research Journal

Over the past 10 years, interleague play has become one of the rites of summer for baseball fans. Interleague play arrives with a lot of fanfare, as so-called “natural rivals” square off while new teams from the other league come to town for the first or second time, theoretically creating a set of unusual and attractive matchups that get the fans excited and boost attendance.

Interleague play is also typically one of the accomplishments cited as part of MLB’s PR campaign to persuade people that the sport hascome all the way back from the devastating strike of the mid-1990s. Along with the Division Series and the wild card, interleague play is given credit by many pundits for reviving interest in the national pastime and pumping up attendance.

Without detailed information from a marketing survey, it’s impossible to quantify just how much extra interest interleague play generates among fans. Regardless, it certainly generates a spate of predictable stories each summer in the media, many of them focused on how much inter-league play boosts attendance. Most of these stories are fueled by the annual press releases from MLB touting the increased attendance in inter-league games as compared to intraleague games.

The Pitch

A July 3, 2006, press release published on boasted that the 252 interleague games in 2006 set records for total fans (8,592,482) as well as average attendance (34,097). It added that interleague play had boosted attendance 13.2% from 1997 to 2006. On the surface, that seems an impressive endorsement of what was viewed as a radical policy back in the 1990s.

These numbers are very misleading, however, mostly because they fail to account for two scheduling factors that pump up interleague attendance and make interleague/intraleague comparison artificially positive. A closer look at this sunny spin on interleague play tells a different story.

Interleague Attendance Analysis

From 1997 through 2006, there have been 2,439 interleague games with an average attendance of 32,838, compared to 20,368 intraleague games with an average attendance of 29,099. On the surface, that would show an apparent increase of 13.2% in attendance for interleague games.

Except in the first year of interleague play in 1997, when some games were played in August and September, about 80% of all interleague games have been played in June, with most of the rest being played in July. Because of that favorable treatment, interleague play starts with a built-in attendance advantage: they aren’t played in the cold weather months and are mostly played after school gets out for the summer.

Taking into account the time of the season when interleague games were played (i.e., normalizing by the day of the year), the weighted average of intraleague attendance becomes 29,763, reducing the apparent attendance increase to only 10%. (The weighted average is calculated by taking the intraleague average for days of interleague play multiplied by the number of interleague games on that date.)

That’s not the only important advantage the schedulers bestow on interleague games, however. Previous analyses of the positive effect interleague play has on attendance have ignored the fact that more than 61% of interleague games have been played on the weekend, compared to only 46% of intraleague games. Scheduling the bulk of interleague games on weekends provides a hidden favoritism and represents an overlooked factor that dramatically changes any attendance assessment.

Taking into account the effects of the days of the week when interleague games have been played, the average of intraleague games on those days is 29,910, making the apparent attendance increase for interleague play also about 10%. When both special factors are considered, we add 664 to the average intraleague attendance to compensate for the day of the year and a further 811 to compensate for day of the week. These adjustments raise the weighted intraleague average to 30,574, which reduces the overall attendance gain for interleague play to only seven percent.

As one might expect, most of the interleague attendance gain was in 1997, its first year, where the apparent (i.e., unadjusted) attendance increase was 33,421/27,727 or 21%. The apparent increase for subsequent seasons (1998–2006) was much smaller: 32,783/29,249 or 12%. The true gain provided by interleague play, then, is reduced to only five percent after the first year (the 32,782 interleague average divided by the 29,248 intraleague average plus adjustments of 970 for days of the month and 904 for days of the week).

Figures Sometimes Lie

All “attendance” figures announced by Major League Baseball and its 30 clubs are actually the number of tickets sold, not the number of people at the game or even the number of people at the game who paid to get into the park. Because MLB no longer announces what used to be called “the turnstile count,” it’s easy to jigger these modern “attendance” figures. Moreover, both individual clubs as well as MLB itself can engage in various maneuvers to pad reported attendance.

One typical way that MLB has spun its attendance numbers in the past few years is by publicizing total attendance instead of per-game attendance. Since baseball expanded by adding four teams in the 1990s, thus adding more than 15% to the number of games played in the past 13 years, these “all-time” records really aren’t that impressive. MLB should be setting records for total attendance because it has more teams than ever before. MLB reported per-game attendance of 31,423 in 2006, a tiny bit higher than 1993’s 31,337 and second only to the strike-shortened 1994 season’s all-time peak of 31,612.

Another, more blatant attendance-padding fiction was engaged in by Florida in 2002. Apparently in order to avoid the embarrassment of having new owner Jeffrey Loria’s Marlins draw fewer fans than his former club—the forlorn, MLB-owned Expos—someone supposedly bought more than 10,000 tickets to the last Florida home game in late September. The club acknowledged the bulk purchase but refused to provide any information about who bought the ducats or why.

A September 30, 2002, story by respected veteran Associated Press sports business reporter Ron Blum, reported:

“Florida drew 813,118, an average of 10,038. On Sunday the Marlins announced a crowd of 28,599—its second largest at home this year—but only about 8,000 fans appeared to be in the ballpark.”

Marlins president David Samson said a long-time fan of the team who lives in south Florida bought more than 15,000 tickets that went unused—which enabled the Marlins to surpass the Expos. Samson said the fan wasn’t affiliated with the organization but declined to identify him.

On a much bigger scale, MLB organized a “charitable” ticket donation in 2004 and 2005 called the “Commissioner’s Initiative for Kids.” This program distributed one million tickets each season to Boys & Girls Clubs and other charities after Ameriquest—one of MLB’s official sponsors— paid one dollar each for those tickets. Because these “charitable” tickets were actually paid for, they were counted in the attendance totals.

How many of those tickets actually put a kid in a ballpark is unknown, but it’s likely that many went unused given that the initiative wasn’t even announced until August 9 in 2004 and until July 27 in 2005. No explanation was given for announcing the initiative about two months after school got out in most cities, especially in the second year of the program, when it could have been announced before the season started.

MLB did not announce any new Commissioner’s Initiative for Kids for the 2006 season. With 2006 MLB attendance headed for another all-time high, perhaps the padding was deemed unnecessary. Or perhaps the lateness of the announcement each season meant the benefit was limited. Or maybe no one cared anymore about the short-lived “initiative” since it clearly wasn’t designed with the primary goal of benefiting children.


Interleague play is only one of the recent innovations that have continued to change the  face and the pace of the national pastime. Scheduling interleague play in large blocks only during the summer months interrupts the flow of the great baseball tradition that Jim Brosnan simply but eloquently dubbed The Long Season in his 1959 diary. In a similar way, the wild card has depleted the excitement of old-fashioned pennant races: the Detroit Tigers celebrated—complete with champagne sprays—clinching a post-season berth in 2006 a week before they lost the AL Central title to the Twins on the last day of play.

Both innovations have positive and negative effects. With the wild card, more teams appear to be in contention for a longer period of time, boosting attendance in cities where interest would suffer late in the season. That’s a real and obvious gain. Yet the wild card also has its less visible costs. It has pretty much made the classic barnburner–kind of pennant race obsolete; after all, if both teams get to advance to the post-season, the pressure and excitement is greatly diminished. Bobby Thomson’s home run surely would never have been dubbed the “Shot Heard ‘Round the World” by New York’s ink-stained wretches if there was a wild card berth in 1951.

In the same way, the extra layer of post-season series simultaneously creates a visible benefit along with a longer, subtler kind of corrosive effect. Clubs that haven’t played in October for years are thrilled to see any kind of post-season action, but teams that perennially make the postseason quickly find that many fans eschew the Division Series, viewing it merely as an extension of the regular season or as a tune-up for the LCS and World Series. The thousands of empty seats seen at so many Division Series games—not to mention TV ratings in the low single digits—testify to the blasé attitude so many baseball fans display toward the first round of MLB’s “playoffs.”

Notwithstanding the measurable benefit, there are very real—if yet unmeasured—costs associated with interleague play that profoundly affect baseball’s popularity and financial health. The dramatic drop in interest in the All-Star game appears to be directly related to interleague play, and the almost yearly setting of all-time lows seen in post-season TV ratings in the past five years— even as announced regular-season attendance was setting records—is also related.

Historically, one of baseball’s core strengths compared to other sports was the attractiveness of its midsummer classic. With interleague play showcasing the stars of one league against the other league during the regular season, the All-Star game naturally loses much of its luster. Thus, the decline in ratings is part of the hidden but very real cost of interleague play.

The same is true of the World Series, where Game One in 2006 garnered an unbelievably low rating—meaning that less than one TV set in 12 was tuned to the first game of the fall classic. The five-game match between the Tigers and Cardinals—a Cinderella team versus an under-dog team, both led by famous managers, both of whom had defied the odds—managed to garner only a record-low 10.1 rating and 17 share. Games three, four, and five of the World Series were not even ranked among Nielsen’s top 10 most-watched prime-time programs for the week, drawing fewer viewers than NBC’s Sunday Night Football, ABC’s Desperate Housewives and Dancing with the Stars, and several different CSI series on CBS.

Now that interleague play has taken the bloom off the All-Star rose, baseball is faced with the Hobson’s choice of cutting out interleague play or changing its traditional All-Star format. Since the former seems unlikely to happen in the near future, MLB has to figure out how to avoid having its midsummer classic become merely an after-thought to its home run-hitting contest, somewhat like the NBA’s slam-and-jam all-star game, or an afterthought to the season like the NFL’s Pro Bowl.

One factor that could not be measured with the available attendance data is the real possibility that fans who plan on attending a certain number of games per season might be more likely to choose an attractive or unique interleague matchup, thus reducing attendance at other games. The extent to which this happens is unknown, but whatever effect it has would create an incorrect appearance of a net gain when it is really just shifting attendance from intraleague games to interleague ones. And it would further reduce the real boost given by interleague play below the current five percent.

While it provides some tangible benefit, interleague play’s effect on attendance is mostly a mirage. When one considers that interleague schedules are engineered to be as attractive as possible, more than half of the apparent attendance gain that MLB boasts melts away. When one considers the double scheduling of “natural rivals” and the rotation of divisions in interleague play, the average five percent advantage realized since 1998 is extremely modest.

GARY GILLETTE and PETE PALMER are co-editors of both the ESPN Baseball Encyclopedia, now in its fourth edition, and the ESPN Pro Football Encyclopedia, the second edition of which will be published in 2007.



Per-game attendance figures quoted in this analysis are technically per-opening numbers. In baseball parlance, an opening is defined as a single game or a doubleheader with a single admission price. Day/night doubleheaders with separate admissions are considered the same as single games. Because of the fact that doubleheaders have rarely been played in the past decade, per-game and per-opening figures are virtually identical.

Unofficial attendance figures as reported in the media were used for this analysis. These attendance figures originate with MLB or with its clubs. There may be some small differences between those figures and the final, official figures released by MLB after the season ends, but they would be very minor.