Why are there so many no-hitters these days? Lack of steroids? Talent dilution? Umpires with big strike zones? There are many theories to explain why there seems to be a no-hitter thrown every week, and why they're being pitched by people we've barely heard of.
Matt Cain's perfect game last night was the 5th no-hitter of the season. And we're not even at the All-Star break. Some are even saying that with so many of these accomplishments (14 in the last 3 years), no-hitters are becoming devalued. They're not as special anymore. Not as impressive.
No-hitters are statistical anomalies. They're freak occurrences. Only 277 of them have been thrown in MLB history. Even with the seeming abundance of them recently, 14 no-hitters in 2.4 seasons isn't as if they're happening every day. Those 14 no-hitters took about 5,800 games to happen. Or once every 414 games. That's 0.24% of games played. 99.76% of games since 2010 have not been no-hitters.
Think of how weird no-hitters are. There's always a great defensive play that defies belief. Sometimes there's a generous umpire. Johan Santana's, for instance, was a foul/fair call away from being just another game. So much has to happen. Every bounce has to go right.
They're so weird, and still so rare, that it's natural for their occurrences to be sporadic and irregular. Sometimes there will be long stretches between them. Between May of 2004 and September of 2006, 6,364 games were played between no-hitters.
I don't think steroids was the culprit for that drought. There were 3 no-hitters in 1999. Mark McGwire hit 65 homeruns in 1999. There were also 3 no-hitters in 2001. Barry Bonds hit 73 homers in 2001. There were no-hitters at the peak of the steroid era.
Furthermore, the lack of PEDs probably isn't the reason behind the recent increase in no-hitters. There have been times when no-hitters came in bunches.
In 1990, there were 7 no-hitters thrown. Two of them on the same day. In 1991, there were also 7 no-hitters thrown. Three of these 14 no-hitters were combined. One was a perfect game.
How many no-hitters were thrown in 1992? One. How many in 1989? Zero.
So the number of no-hitters went from 0 to 7 to 7 to 1.
If you're going to do analysis on a trend, look at the entire history of the trend. The article I linked to pointed out that 5.7% of all no-hitters have occurred in the last 2.5% of seasons played. This analysis ignores the fact that until 1960, there were only 16 MLB teams (so far fewer games played in a season). And it also makes it seem like this is a huge rash of no-hitters. An epidemic. An unprecedented epidemic.
But as I pointed out, 5.1% of no-hitters were thrown in 1990 and 1991. The number of no-hitters can rise and fall with significant variance from year to year. There doesn't have to be a significant cause. It's just random.
Now, if there are 10 no-hitters this season, then 8 more next year, and 8 more the year after that, I'll agree that this is a trend. Until then, it's not. It's just statistical randomness of a random and weird event.
And I'm still impressed by them.