Jay Bruce and the Problem with Player Evaluation

From the start, Jay Bruce has done just what every fan wants to see from a young player who just signed a contract extension. He started out on fire, going 15 for his first 30, with three doubles and four homers. Of course, a .500/.531/1.000 line wouldn’t last forever, but it put everyone at ease, especially after his .306/.376/.575 line in the second half of 2010. He has streaked and slumped a bit since then, as one might expect. After an 0-for-3 performance last night he’s down to .282/.349/.535, though those are still quite excellent numbers — a .386 wOBA, which ranks sixth among NL outfielders. If he catches fire again, he could start climbing that leaderboard again.

Only, that’s not exactly true. Yes, Bruce does have a .386 wOBA, and that does rank sixth among NL outfielders. But it took Bruce a while to get there. In fact, the streak described above is currently happening, while the slump, including that 0-for-3 performance, occurred a bit earlier in the season. It doesn’t change the end result, but it does change the narrative.

Right now Bruce is at or above the level of play expected of him, but it took him a while to get there. He started the season in a pretty massive slump, going 9 for his first 41 with two doubles and three walks. It wasn’t until his 49th plate appearance that he smacked his first home run, a tack-on at the end of a 6-1 victory over the Pirates. It was the day after that homer that our own Howard Bender, writing for RotoGraphs, preached patience with young Bruce. It was clearly the right message, since his season started to turn around right there.

Still, it wasn’t a smooth transition back to the top. After a mini surge Bruce again fell into a slump, and after going 0-for-3 with a walk on April 26th he was hitting just .226/.290/.357. It took him a while even then to pick himself up; as recently as May 14th he was hitting .236/.312/.436. But then he went on the above-described surge, which has essentially corrected the wrongs of the early season and has placed him back in the company of the league’s elite outfielders.

I have to wonder how a change in the order of how Bruce got to this point changes the narrative of his season. When I first started this, it was a bit on how this recent surge has taken pedestrian numbers and turned them into superstar numbers. And, of course, because hot streaks don’t last forever it’s easy to say that he’ll cool down, and his wOBA will drop a bit. But then re-read the first paragraph. It just changes the order of events to have the streak come first, followed by the slump. In that scenario, we might expect Bruce to go on a surge again sometime soon — slumps don’t last forever, either.

The fickle nature of small samples makes analyzing players difficult at this point in the season. It feels in many cases as though we’re telling a story about a player, or describing a certain process, rather than pinning down anything predictive. That’s just the nature of the beast. Bruce might be the best example of that. There is absolutely no telling where his season ends up. Maybe he’ll continue this streak, bring his wOBA up to .420 or so, and then cool back down and stay at the .386 level. Maybe he’ll cool down in the next few games and settle at around .363, as he did last year. There’s no real way to tell, given the information we currently have available. That doesn’t diminish Bruce’s surge-and-slump season. It just highlights an issue we all face when evaluating player performance, even at the 200 PA mark.




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Joe also writes about the Yankees at River Ave. Blues.


64 Responses to “Jay Bruce and the Problem with Player Evaluation”

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  1. Babip Avengers says:

    Bruce was 3/4 with a HR last night, not 0/3 as the first paragraph suggests.

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  2. Clint says:

    Not sure what you’re looking at. He didn’t go 0 for 3 last night, nor did he start this season ‘on fire’ and 15 for 30.

    Other than that, decent post.

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    • Ballens says:

      The post is especially good if you read the whole thing!

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    • Big Jgke says:

      If he was ‘on fire’ as the first paragraph of this post suggests, wouldn’t he have hit the DL with a fire-related burn injury by now?

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      • quincy0191 says:

        And if he really was slumping, wouldn’t his hitting coach have said something about it and told him to stand straighter at the plate?

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  3. Everett says:

    It seems reading comprehension is really lacking here today

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  4. Minstrel says:

    I have to say that I’m a little confused by the point of this piece. Are you saying that this is a problem in mainstream baseball evaluation? Because no “advanced” evaluation that I’ve ever seen uses narrative or ordering of slumps and streaks to attempt to figure out a player’s “true talent level.”

    It is definitely true that the sample size is too small to make any definitive statements about any player’s current season…but that’s not an issue of the order in which Bruce slumped and caught fire. We all know, or should know, the baseball performance is the most volatile of all the major sports game to game and week to week so, barring injury or something material of that nature, there’s little to no importance in the way a player reaches his numbers, as far as when he got hot and when he was cold.

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    • Joe Pawlikowski says:

      It’s more that there is no way to perform an “advanced” evaluation of a player at this point. We can look for clues and indicators, but until we’re at the 400-500 PA mark we’re still using a lot of narrative in our evaluation. I know that many analytical purists resent that, but I think it adds another dimension to baseball writing. It shouldn’t be solely, or mostly, what we base our evaluation on, but it always ends up playing a role. I just wanted to take a look at how it can work, or not work.

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      • Oscar says:

        The narrative has nothing to do with the evaluation, since it tells us nothing, which is borne out by your post. In fact, the narrative is often worse than nothing, since it states ideas like “Jay Bruce is streaky” when there’s pretty compelling evidence that there’s no such thing as a streaky/consistent player.

        So…are you saying that we have to be careful to avoid getting sucked into early-season narratives, because it clouds accurate evaluation? If so, I agree. If not, I don’t really know what your thesis statement is. Could you clarify?

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  5. Dan says:

    I’m confused by this article.

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    • JohnnyBigPotatoes says:

      This is an article posted in fangraphs/blogs, not in rotographs. It is about the trickiness of evaluating a player at a moment in time, since telling a story about a player in a narrow context is difficult without arbitrary beginning and ending points. Jay Bruce is the example. Howard doesn’t seem to advocate one set of predictions for the rest of his season over another. If he did, you would probably find this on the /fantasy side. I thought it was a smart piece.

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  6. Ed says:

    IMO, point of article: What we project for a player’s future performance is often influenced (tainted?) by the narrative surrounding the player. Depnding on the order of the hot streaks and slumps (and the hottness and slumpiness thereof) we come to different conclusions about where a player will end up.

    Slumping players who go on a hot streak are “figuring it out” while players who start out hot and then slump are “falling back to earth”. Thus, people project players differently even when the respective data (apart from the ordering) is identical.

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  7. Clint says:

    I get it now, but its poorly written.

    The author is trying to show us that in evaluating the season of a ballplayer a slump to start a season should not be taken so seriously; because if the player starts on fire like Bruce has been in May, then they’re conceived as having a great year–even if they slump a few months into the season.

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  8. Clint says:

    Another thing the writer should take into account is that few players surge and slump like Jay Bruce. Some travel along a more even plane. Bruce deals in extremes. So that’s another problem with player evaluation.

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    • Josh Shepardson says:

      That’s a bit of hyperbole no? We’re talking about a player with just over 1600 plate appearances who also suffered a broken wrist which may or may not have been the reason for his poor power output at the beginning of last year. Seems a bit premature to declare him amongst the streakiest of players if you ask me.

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    • mattinm says:

      I’m pretty sure there was an article written earlier in the year on here disproving the existence of ‘streaky’ players. Or at least showing that there is no year-on-year correlation to the ‘streakiness’ of a player.

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  9. Scott says:

    This article is indeed poorly written. The main point of an article should be crystal clear to the reader by the end, and it certainly isn’t in this case.

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  10. mcbrown says:

    Great article. Patience is important – it’s a long season. Everyone has ups and downs, and the order doesn’t matter so much even if it feels like it does.

    Now please excuse me while I dissect each of Carl Crawford’s recent plate apperances in exquisite detail for signs that he is about to catch fire.

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  11. dnc says:

    Allow me to chime in and say I enjoyed the article greatly, and thought the main point was crystal clear. Thank you for putting this together.

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  12. TFINY says:

    I really enjoyed the article. I didn’t find it hard to understand, and I got the point clearly at the end. Just thought that I would provide my opinion, as it seems to be in the minority.

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  13. dudley says:

    instead of evaluating players in terms of PAs that have occurred this season, we should probably be looking at a moving average that includes PAs from the past season, to get us to a reasonable sample size. the problem is that it’s a lot more work to slice & dice the numbers that way.

    one question i have is, if we’re considering, say, a 600 PA moving window, whether we should weight all the PAs equally, or try to attach more weight to the more recent PAs, which might have more predictive power in terms of a player’s current physical state, plate approach, swing mechanics, etc.

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  14. Wez says:

    I totally get your point and it is a very interesting take but I also agree with some of the readers that it was rather confusing.

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  15. Jason461 says:

    In reading some of the comments to this article, I am reminded of conversations I have with some of my students (I teach high school English).

    Student: I don’t understand this.
    Me: Did you read it?
    Student: No, but I skimmed it.

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    • TylerTheCreator says:

      There is a difference between being able to understand something and it being well written. I understood the article, but it wasn’t well written.

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    • bcp33bosox says:

      Hahaha…lol, classic! Nice one, Jason!

      And Tyler, it was a bit of a creative piece. You may not like the article or the writting style, but *that* is different from it not being well written. The author seemed to want us to do a double take, which further emphasized his point on evaluating players and how we may be influenced by narratives. Futhermore, based on many of the comments, there were plenty of people who did not undertsand. I am guessing most likely as a result of either skimming it, or lack of actual reading comprehension…my guess would be becasue they skimmed it as Jason suggests. It states very clearly that:

      “In fact, the streak described above is currently happening, while the slump, including that 0-for-3 performance, occurred a bit earlier in the season.”

      Therefore, the criticism of it not being well written seems to be harsh and leads me to wonder what writing review credentials those commenters have. Personally I liked it and I thought the author’s point was clear by the end of the article.

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  16. Neuter Your Dogma says:

    I am in the good article camp, although posing it as a hypothetical at the beginning, to me, would have been helpful because I would have fallen into the narrative trap with my own conclusion before the “gotcha.”

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  17. Rick says:

    Love the article, but the creative structure isn’t quite evident enough. It’s not clear that the beginning paragraphs are based on a reordering of his performance. I think the same point could have been made more effectively by actually playing out the approach more fully and then more clearly making the reveal.

    Tell the narrative backwards, with it “ending” with Bruce going .220/.267/.268 over the last 10 games (his real first 10 games) to bring his seasonal lines down to where they currently sit. Then pose the questions about whether or not he’ll rebound back up to .400 wOBA or whatever. Do all of that, playing it completely straight and then clearly inform the reader of the trick and its implication on our perceptions.

    I think that would have made much more sense.

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  18. Rick says:

    Maybe it needs to be said more explicitly:

    Over the course of a season, the order in which things happen has no predictive value. That is to say, what a guy is likely to do next is a function of our estimate of his true talent and nothing to do with how well he’s hit recently.

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    • B N says:

      It clearly DOES have predictive value. I mean, if a guy hurts his wrist and then starts slumping- that’s pretty darn predictive. With that said, there’s enough other noise that the order’s predictive value is low.

      But it’s definitely non-zero.

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  19. adr3 says:

    Allow me to point out the irony of the situation. Some of us are pretentious, and therefore we enjoy commenting on how poorly the article was written. Others of us, are also pretentious, and enjoy pointing out the fact that the article is written fine, but the aforementioned pretentious folks are actually retarded. Doesn’t that mean in some strange way, that we all agree to be happily pretentious?

    I would like to suggest a third, neutral perspective: Since I pointed this out, I’m the most pretentious….we’re all retarded…and umm go Cards….

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  20. Random Guy says:

    Oh, I see now. This article is like a Tarantino movie where it jumps around temporally and we’re supposed to orient ourselves or otherwise be all like “hey, there’s Vincent Vega again, didn’t Butch mow him down a couple of scenes ago?”

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    • B N says:

      Just be lucky it’s not done Memento style. He’d write a coherent, logical analysis in order, then start the article with the last sentence of that argument, followed by the second to last, etc- until he reached the first sentence at the very end.

      “It just highlights an issue we all face when evaluating player performance, even at the 200 PA mark. That doesn’t diminish Bruce’s surge-and-slump season. …. (other sentences) From the start, Jay Bruce has done just what every fan wants to see from a young player who just signed a contract extension”

      Sounds pretty good actually. We should start trying this and see if it hurts coherence. :)

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  21. Bpdelia says:

    Why does everything either have to be a “great” article or “worst pos ever”? Can’t it just once NOT be one of those two? It was alright. The writing was decent though it lacked a strong lead. The analysis was interesting but not great”. It was fine. Certainly not great but not as streaming pile. Why is it that when people comment in the internet nothing is ok? Christ.

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  22. hildebeast21 says:

    when determining the value of a player, the manner in which he achieved his final production is of obvious importance. too much volatility isn’t a good thing in baseball either.

    i like to use the sharpe ratio:

    [wOBA(Player in question) - wOBA (replacement at his position)]/(standard deviation of wOBA of player in question over the appropriate time period)

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  23. Antonio Bananas says:

    This is the part where I say “let’s just use normal statistical measures like confidence intervals and variance”. Why invent all these statistics that you have to teach everyone that someone (a lot of times) without a real stats background made up? How about just use variance? What’s his series to series average and the variance of that? Or his week to week? Or his 20AB? If a guy bats .300 every month, isn’t he more valuable and better than a guy who bats poorly every month, then has a month long stretch of hitting .500? Use normal stats guys, it’s not that hard and they make a lot of sense.

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    • Dan says:

      Mr. Bananas, are you sure that a consistant .300 every x interval is better than the .200/.500 guy? Or even that consistancy is a repeatable skill over a career?

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  24. Slats says:

    I like turtles.

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  25. TheGrandSlamwich says:

    I think this must have been a very difficult article to write. Writing for a statistically based website about a young player while attempting to take into account the law of small sample sizes sounds like a big challenge. I think JoePaw did a solid job.

    It should be noted that Bruce was rated as the top prospect in baseball in 2008 by many ranking systems (above Longoria and Votto). The average may not stay up but his power is for real, not to mention he led the league amongst rf’s last year in UZR.

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  26. WhatLeylandNoooo says:

    Clearly the last sentence of this article should have been, “Now imagine he’s black.”

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  27. supgreg says:

    My favorite part is one of the last lines in the article:

    “There’s no real way to tell, given the information we currently have available. ”

    You mean you can’t tell the future? Really? /end sarcasm

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  28. blahblahblah says:

    Cognitive dissonance.

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  29. BlinkULDHC says:

    Look, I get the rhetorical/creative purpose of the cutesy “got ya!” flip-flop of the stats, but the execution hurt the article more than it helped.

    It’s a Catch-22 problem with the “got ya!” trick. You need the reader to buy into the 1st paragraph’s statistical SET-UP (i.e., Bruce started hot and then cooled down), and then you need the reader to care about the 2nd-3rd paragraphs’ statistical REVEAL (i.e., Bruce is actually on a current hot streak after starting cold). It just doesn’t happen here.

    Many or most of those who read this article probably have been following Bruce closely enough to know that the 1st paragraph’s stats are incorrect (i.e., Bruce didn’t start hot), rendering the “got ya!” ineffective. If you reject the 1st paragraph set-up of stats as incorrect/fictional, then there’s no point or value to the reveal of the real-life stats.

    The remaining readers (who don’t suspect anything wrong with the stats in the 1st paragraph) probably don’t care about the “got ya!” statistical reveal. If you didn’t immediately call BS on the 1st paragraph stats, you probably also don’t care about in what order Bruce had his slumps & streaks in ’11, nor would you internally debate whether to be “patient” with JBruce during early protracted slumps in ’11, etc…. and the “got ya!” still doesn’t work, since these readers just don’t care enough.

    It’s also incredibly distracting to stop reading the article just to fact-check after 1 paragraph. If you started the article with, “Imagine if…”, then readers would take the 1st paragraph stats at face value and proceed on reading the rest of the article. Yes, you may lose your cutesy rhetorical hook, but at least you won’t confuse the heck out of more-than-casual MLB fans and/or JBruce fans. By stating the 1st paragraph as a seemingly-absolute truth, some of us neurotic fact-checkers cannot keep reading until we, um, fact-check!

    Bottom Line: those who’d care about the reveal probably didn’t buy into the set-up, and those who bought into the set-up probably didn’t care about the reveal.

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    • BlinkULDHC says:

      Also, the points in the article would have been better demonstrated by comparing two separate players with similar season-totals but with different orders of streaks/slumps.

      Player A is hitting .300 and started the year 30-for-60.

      Player B is hitting .300 and is currently 30-for-60.

      How do you like them apples?

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  30. moo says:

    clearly the article was read by those that follow joe pawl or jay bruce and was very efffective as spurring reader commentary…i read it all too.

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  33. Cuban Pete says:

    Now this post, the shopping post, is really well-written and has a strong narrative flow.

    Yikes!

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