Let’s Review Some Reader Predictions
Nearly eight months ago, I asked you to predict the future. Here are the words I used to introduce that piece:
In 2017, the fastball rate fell again. It’s been falling for some time now, but in 2017 it fell again, from 56.7% in 2016 to 55.6% last year. There’s some reason to think that the drop in the fastball rate is linked to the increase in baseball’s increasing swinging-strike rate, which in turn is linked to the rise in strikeouts and hit batsmen, and on and on and on. Baseball is a complex system of action and reaction, and small changes can grow large quickly.
So this year, I want to know: what do you think will happen to some of baseball’s key stats, league-wide, in 2018? Maybe you think home-run rates will go up and strikeouts will fall. Maybe you think if home-run rates go up then strikeout rates have to fall. Maybe you think it’s the other way around. I don’t know. But I want to hear from you, and most of all I want to hear why you think certain changes are linked, and others aren’t.
Below are a series of tables featuring 10 years’ worth of data for a few key metrics. I’ve also included percentage changes year over year. Below each table is a poll which asks you to indicate whether you think a given statistic will increase or decrease — and, if so, by how much. Answer each poll, if you wish, and then also indicate in the comments why you voted the way you did on one statistic and not others. In a year or so, I’ll come back to this and we’ll talk about it as a group. Maybe it’ll be interesting. Maybe it won’t! We’ll see.
A lot has happened since I wrote those words: I’ve gotten married, my wife and I moved from Boston to Seattle, and I became a telecommuter (in my day job; this one has always been virtual-only). Oh, and the 2018 season came and went. The future I asked you to predict is now a part of the history books. Let’s see how good you were at reading ahead.
Note: a reader of the March post suggested he/she was unsure if answers should be submitted in percent or percentage point. It’s possible, as a result, that a few ballots could distort the overall results. Because I presented all the original deltas in the form of a percent, however, that is how I have once again presented them here. Fortunately, none of this matters at all!
Fastball Rate
| Year | FB% | FB% Delta |
|---|---|---|
| 2008 | 60.7% | n/a |
| 2009 | 59.7% | -1.65% |
| 2010 | 58.7% | -1.68% |
| 2011 | 57.8% | -1.53% |
| 2012 | 57.6% | -0.35% |
| 2013 | 57.8% | 0.35% |
| 2014 | 57.7% | -0.17% |
| 2015 | 57.7% | 0.00% |
| 2016 | 56.7% | -1.73% |
| 2017 | 55.6% | -1.94% |

Walk Rate
| Year | BB% | BB% Delta |
|---|---|---|
| 2008 | 8.7% | n/a |
| 2009 | 8.9% | 2.30% |
| 2010 | 8.5% | -4.49% |
| 2011 | 8.1% | -4.71% |
| 2012 | 8.0% | -1.23% |
| 2013 | 7.9% | -1.25% |
| 2014 | 7.6% | -3.80% |
| 2015 | 7.7% | 1.32% |
| 2016 | 8.2% | 6.49% |
| 2017 | 8.5% | 3.66% |

Strikeout Rate
| Year | K% | K% Delta |
|---|---|---|
| 2008 | 17.5% | n/a |
| 2009 | 18.0% | 2.86% |
| 2010 | 18.5% | 2.78% |
| 2011 | 18.6% | 0.54% |
| 2012 | 19.8% | 6.45% |
| 2013 | 19.9% | 0.51% |
| 2014 | 20.4% | 2.51% |
| 2015 | 20.4% | 0.00% |
| 2016 | 21.1% | 3.43% |
| 2017 | 21.6% | 2.37% |

Out-of-Zone Swing Rate
| Year | O-Swing% | O-Swing% Delta |
|---|---|---|
| 2008 | 24.9% | n/a |
| 2009 | 25.1% | 0.80% |
| 2010 | 28.7% | 14.34% |
| 2011 | 29.9% | 4.18% |
| 2012 | 30.3% | 1.34% |
| 2013 | 30.4% | 0.33% |
| 2014 | 30.7% | 0.99% |
| 2015 | 30.6% | -0.33% |
| 2016 | 30.3% | -0.98% |
| 2017 | 29.9% | -1.32% |

Contact Rate
| Year | Contact% | Contact% Delta |
|---|---|---|
| 2008 | 80.7% | n/a |
| 2009 | 80.5% | -0.25% |
| 2010 | 80.7% | 0.25% |
| 2011 | 80.7% | 0.00% |
| 2012 | 79.6% | -1.36% |
| 2013 | 79.4% | -0.25% |
| 2014 | 79.3% | -0.13% |
| 2015 | 78.8% | -0.63% |
| 2016 | 78.2% | -0.76% |
| 2017 | 77.5% | -0.90% |

Home-Run Rate per Fly Ball
| Year | HR/FB | HR/FB Delta |
|---|---|---|
| 2008 | 10.1% | n/a |
| 2009 | 10.1% | 0.00% |
| 2010 | 9.4% | -6.93% |
| 2011 | 9.7% | 3.19% |
| 2012 | 11.3% | 16.49% |
| 2013 | 10.5% | -7.08% |
| 2014 | 9.5% | -9.52% |
| 2015 | 11.4% | 20.00% |
| 2016 | 12.8% | 12.28% |
| 2017 | 13.7% | 7.03% |

*****
What have we learned? Well, first, I’m impressed that most of you got most of these right. I guess I shouldn’t be. You all watch a lot of baseball and can read tables reasonably well. You get the crowdsourced contracts generally right, too. I shouldn’t have doubted you.
That’s the first thing. The second thing I’d take away from this is that most of the trends that have made baseball baseball in the last few years — lots of power, lots of strikeouts, and declining contact — stayed the same or accelerated in 2018. Yeah, the home-run rate per fly ball dropped in 2018 — and the number of home runs dropped accordingly — but players still hit a lot of home runs: more by nearly 700, for example, than they hit in 2015, which was itself one of the highest totals of its decade. And we, once again, saw fewer fastballs and more strikeouts this year than we ever have before. So, thanks for reading, and thanks for getting this right. Come back and play again next year. I miss baseball already.
Rian Watt is a contributor to FanGraphs based in Seattle. His work has appeared at Vice, Baseball Prospectus, The Athletic, FiveThirtyEight, and some other places too. By day, he works with communities around the world to end homelessness.
“And we, once again, saw more fastballs and strikeouts this year than we ever have before.” Didn’t the fastball rate go down, and not up?
I assume that’s a typo, and he meant to say fewer fastballs. There’s also a word missing in the first sentence after the big blockquote at the beginning of the article.
Both are fixed — thank you!
The out of zone swing rate increase and the HR/FB ratio decrease make a lot of sense to me, having watched a lot of baseball this year and especially the playoffs.
Taken together, I think this is a sign that the launch angle revolution is reaching diminishing returns. The guys who should be swinging for the fences almost all the time starting doing so a few years ago- now, lots of others with less power are doing so, leading to more swing and miss on low and outside sliders and more medium fly balls (the Dodgers flailing away in this manner during the WS exemplifies this approach)
The Dodgers approch worked well throughout the regular season as they were one of the best hitting teams in the league. Their approach was not what caused them to lose the series, they just didn’t have a good series. Nice try John Smoltz.
I would have guessed the HR/FB rate would drop if for no other reason than the effect of the mysterious “juice balls” have been lessened somewhat in recent years + the Chase Field humidor
To be fair the hr flyball rate is likely related to a slight de juicing of the juiced ball, nobody could have predicted that.
I was hoping this was going to be an article holding readers who post their predictions in the comments of “Bold Predictions” articles (often with snide commentary) to account. Would really love to see that!!