"Moneyball"/RBC

In short, baseball is getting quantitatively less exciting, and fewer people watch with each passing year. Why?

The obvious answer—so obvious that its obviousness seems to dispel other explanations—is the rule against steroids. In the spring of 2006, Major League Baseball implemented a new drug policy, banning more than 100 substances and threatening one-year suspensions for two-time violators and lifetime bans for three-time offenders. You might say that performance-enhancing drugs were the chemical tailwind behind the home-run bonanza. When baseball banished them, the tailwind died, and hitters’ un-enhanced strength has proven inferior. Since 2006, the same year baseball introduced its drug policy, total home runs have fallen in a herky-jerky pattern. Total slugging, a more complete picture of power hitting, has eroded more steadily.

The End of Offense

League-wide home runs and slugging percentage: 1998 - 2013

Yes, steroids pumped up offenses, and yes, the rules against steroids have deflated them. But something else happened in 2006—something that baseball fans rarely talk about when they bemoan the offensive state of baseball. It wasn’t something that baseball took away. It was, rather, something that baseball added.

A camera.

Umpiring the Umpires

On October 4, 2006, the Minnesota Twins hosted the Oakland Athletics in a first-round playoff game at the Metrodome. When the first pitch left Esteban Loaiza's fingers, a first-of-its-kind camera tracked the pitch’s speed, break, and location, and relayed the data points to broadcasters and online viewers. By 2008, cameras with this Pitch f/x technology were installed in every stadium, capturing 95 percent of all balls and strikes, according to Hardball Times.

Rather than deem the cameras a threat to league integrity, baseball embraced them. For years, Major League Baseball had been pressuring umpires to submit to performance standards. With the introduction of Pitch f/x, MLB finally had cameras in every stadium to umpire the umpires. In 2009, the league implemented a policy called Zone Evaluation (ZE), which tracked missed calls after each game and judged umpires by their accuracy. After ZE's first year, three senior umpires were fired for their mistakes behind the plate. Those with good performance could get promotions and earn up to $400,000.

Better incentives make better workers. As economist Edward Lazear has shown, organizations become more productive when a job well done is rewarded with extra money and dumb mistakes are punished. So we shouldn’t be surprised that, after the introduction of cameras, umpires have called the strike zone more consistently and more accurately each year since 2007, as Brian Mills explained in a brilliant paper.

Cameras Made Umpires More Accurate

The strike zone morphed in the age of camera technology, as well. Before cameras, it turned out, umpires had been ignoring strikes around the knees. Pitches between 18 and 30 inches above the plate, which are technically in the strike zone, had been called balls for years. But the presence of cameras encouraged umpires to lower the strike zone.