Everyone talks about recency bias in the context of baseball – the tendency to overrate small-sample, recent streaks as more meaningful and predictive than they actually are – but there is another big bias that I find hits us fans especially hard: primacy bias.
You know all about this bias, even if you don’t realize it. The primacy effect is the tendency to better remember/emphasize the first piece of information we encounter than information presented later. For fans of baseball, it manifests itself most obviously when you’re talking about a player who is new to a team, and has really crummy performance early on. It can take an unreasonably long stretch of good – maybe average-for-their-career good – performance to wipe away a very small sample of terrible performance out of the gate. That sticks with fans much longer than it should thanks to the way our brains work. Good job, brain.
It also tends to manifest itself in situations where an entire positional group – perhaps especially one that we were already predisposed to worry about – lays several consecutive eggs to open a season.
That was the case with the Chicago Cubs’ bullpen, which I think we’d all pretty roundly regard as some version of “crummy” this year, even as virtually all of the bad performances came only at the outset of the season.
How stark is the primacy bias in this one? Well get this, we can look at the whole of the bullpen’s performance this year and be struck by how it FINALLY rates as not terrible:
Folks, I have incredible news.
The Chicago Cubs bullpen is very nearly middle of the pack now!!! pic.twitter.com/3ydH6QZJKm
— Bleacher Nation (@BleacherNation) April 30, 2019
But actually, my tongue-in-cheek tweet does not do the Cubs’ bullpen any kind of real service.
Since April 7 – the day after the Cubs significantly shook up the early-season bullpen by optioning Carl Edwards Jr. and placing Mike Montgomery on the Injured List – the Cubs bullpen has a 2.00 ERA. That mark is THE BEST IN BASEBALL BY 0.38 RUNS, AND THERE IS ONLY ONE OTHER TEAM UNDER 3.00! Did I type that loudly enough?
Oh, also … THEY HAVE THE BEST FIP IN BASEBALL DURING THAT STRETCH, TOO. I AM TYPING LOTS OF THINGS LOUDLY.
Interestingly, the primary way the Cubs are pulling this off is by holding down home runs to an extreme extent – not a bad trick in an offensive environment where home runs are exploding and everyone is trying to hit them. The Cubs bullpen’s groundball rate since April 7 is an unthinkably high 53.5%, nearly SIX PERCENTAGE POINTS HIGHER than the next team in baseball.
To be sure, I don’t think *this* level of success is quite sustainable, but I do wonder just a bit about the broader point Theo Epstein made about where things stand, per NBCSC: “As tough as our start was, it could be good for us in the long run. We got tested early. You find out a lot about individuals and a team when there’s adversity. Even though it’s early, even though we’ve all been through it before, when you get off to a really rough first week of the season in a big market, there are a lot of doubters. It can push guys; it can test guys. I think they’ve certainly responded the right way by recommitting to the routines and the foundation and each other and pulling out of it. It’s a real positive sign. Let’s be honest — it was really our pitching the first week or 10 days of the season that was putting us in that destabilized mode and then the pitching’s been outstanding since then.”
Maybe, at least some teeny, tiny part of the bullpen’s significant success these last few weeks has been tied to getting their heads on straight and their routines in place precisely because of the rough beginning. I would guess that sorting out roles has at least as much to do with it, as well as just normal positive regression. But still, I suspect Epstein knows just a little something about this, and, whateves, I choose to be a little positive about the bullpen right now.
Even if and when things take a southward turn – and it is a virtual statistical lock that, for some stretch, they will – the Cubs do have significant big-league-plausible depth in the minor leagues right now, including rehabbers Montgomery, Tony Barnette, and Xavier Cedeño, big league work-it-out-er Edwards, and talented guys like Tim Collins, James Norwood, Randy Rosario, Rowan Wick, Alec Mills, Dakota Mekkes, and more.
TAKE ME AWAY, RECENCY BIAS!