Embracing numbers or: Why I learned to watch the game AND use statistics

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Anyone that follows me on twitter or that has read any of my pieces here at MLHS knows that I enjoy using possession statistics alongside production statistics to examine and evaluate players. After recent events, like Lupul’s tweets and Alec’s interview with Greg Cronin, that have stirred up the tension between those that use these statistics and those that don’t, I thought I’d dig into why the use of statistics should be embraced.

A few common responses that I’m seeing to the use of statistics in general, but especially possession statistics, are “watch the game, statistics don’t tell you everything,” or “watching the game tells me everything I need to know” or even “statistics are basically magic.”

The first response isn’t incorrect. In fact, there are very few (if any) bloggers that would tell you statistics are all-encompassing measures of a player. Many bloggers (and fans) use a combination of video evidence and collected statistics to evaluate and compare players, teams and coaches. Disgraced journalist Jonah Lehrer wrote an article about the problems with sabermetrics in baseball (mainly that people are fixating on these numbers as the be-all and end-all) and Bill Petti wrote a critical response that has a great (and relevant) quote:

[pull_quote_center]… Lehrer’s main argument shouldn’t be that teams are assembling bad teams because of a narrow-minded focus on things they can quantify. The argument should be that teams that don’t think deeply about what are the right metrics and how much variance they account for in player achievement will fail just as much as those teams that used to generally ignore analytical approaches to the game. Data and statistics are not to blame for bad decisions–their misapplication is.[/pull_quote_center]

What I love about this quote is that it echoes something that I’ve said in response to Cronin’s interview with Alec: that just because an NHL team is using certain statistics to make decisions, doesn’t mean that method is the right way to proceed. In other words, I’m warning people about confusing what is and what should be.

The third response seems pretty silly to me and since there really aren’t that many people forwarding that view I’ll leave it at that.

The second response isn’t necessarily incorrect, but it’s highly unlikely and that’s really what I want to focus on in this piece.

Why is it highly unlikely that watching the game tells you everything you need to know? It’s a great question and there are multiple challenges.

Let’s start with the old adage “practice makes perfect,” and apply it to responses about how much hockey you’ve watched. Well, as it turns out, that adage should really go proper/perfect practice makes perfect.” The idea that I’m trying to convey here is that just watching the games isn’t enough to have you excel in understanding hockey. You’ll need to approach watching hockey in a systematic way that pushes you to your limits and that aims to improve your ability to understand hockey. This, in part, brings us back to the idea of needing know what we need to be focusing on and what events are important to understanding how to evaluate players, coaches and teams. Cue the next challenge.

Let’s say that you have a systematic approach to watching hockey and now you want to know what events you need to focus on. People are influenced by conspicuity (how eye catching something is), and so when deciding what to focus on, that’s likely where you’ll start. This is where you’ll run into the challenge of inattentional blindness. Inattentional blindness occurs when you don’t notice an unexpected event in your field of vision because you’re focusing on another event.

Why does this matter when watching hockey? If you’re focusing on the conspicuous events (possibilities: goals, hits, big saves) then you’re less likely to notice less conspicuous events (possibilities: set plays, zone exits/entries, pre-shot positioning) and you’re more likely to see what you expect to see (perhaps why Cronin thought he saw Grabovski turn the puck over in game 7). Inattentional blindness shows that even if the event is conspicuous, like a player entering the attacking zone, if you don’t know to look for that event and you’re focused on something else, like a hit that just happened, you’d likely miss the zone entry. Good news though: once you know to look for certain things they become easier to spot. The problem is that you can’t focus on everything.

Now, let’s assume that you have a systematic approach to watching hockey and you know what you want to focus on. After a game, or a season, is over and you go to evaluate a player (or coach or team), you first have to recall everything you’ve seen and despite your system and focus, your mind will play tricks on you. Most people think the brain works like a video camera that stores your memories perfectly, but the reality is that your memory is malleable, stored in pieces and events reconstructed every time you call on it. When you listen to the commentators describe the game, the way you remember the events they are talking about is influenced by the terminology used. For example, stronger phrasing, like “bulldozed” over “hit”, can lead to altered memories to support the phrasing (meaning you’ll remember the hit as bigger than it was).

On top of that, negative memories are more accurate than positive memories and studies lead to the suggestion that “individuals in a negative mood process information in an analytical and detailed fashion, whereas people in a positive mood rely on broader schematic or thematic information and ignore the details.” (Note: This is probably an important piece of information to keep in mind for Leafs fans as we head into next season after making the playoffs for the first time since 2004.)

Despite your system and your focus, not only is your memory unreliable and malleable but your mind is also subject to cognitive biases and heuristics (mental short-cuts that make problem solving simpler) that impact your judgment and decision-making. There are many heuristics and cognitive biases but I’m going to narrow the focus to just a few big ones (though I strongly encourage you to look at as many as you can).

Let’s take a look at availability heuristic first. This heuristic occurs when you assign the probability of an event occurring based on the ease with which you can recall a similar event to mind. So, you see a player turn the puck over (and because that may be a negative even you may be more likely to remember it) during the season and it lead to a goal against. When you try to recall how this player is defensively and that image jumps into your head, you’re more likely think that it’s a frequent occurrence even though it may not be. It’s worth noting that the images called to mind don’t have to be memories, imagined scenarios work just as well.

Next on the list is representativeness heuristic. This heuristic states that when slotting objects into multiple classes, the probability with which an object belongs to a class is dependent upon the degree to which that object is representative of the stereotype of that class. Very wordy, but a simple example is the stereotype of defensive-defensemen being big, mean, crease-clearing machines and then asking you whether a 5’10 defenseman that looks honest and plays cleanly is a defensive defenseman.

Confirmation bias is a tendency to favour information that supports your preconceived notion, irrespective of the validity of that information. This leads to the selective use of memory and information gathering skills. For example, you are more likely to remember or notice giveaways by a player that you think (rightly or wrongly) is a turnover machine.

The halo effect is another bias that can have a large impact on decision-making. This bias occurs when the perception of an element of an object spills over into other elements of that object. This can result in the evaluation of a player that exhibits generally likeable aspect to their game like blocking shots (*cough* Tim Brent *cough*) or physical play being more favourable than otherwise would be the case. The opposite bias (less favourable evaluation due to spillovers from a negative aspect) is the horn effect.

So, even if you are observing the game properly and know what to look for, your observation and interpretation of the game and the results are inherently biased and your memory unreliable. Hopefully, you are beginning to see the potential interaction between some of these phenomena and why they complicate observation, recollection and evaluation.

What’s the good news? Using statistics can help overcome some of these challenges (though they also present some different ones) by attempting to provide objective accounts of transpired events that can act as fact checking measures on what we perceive, observe and remember.

I’ll leave this monstrosity of an article (though there is a lot unsaid and I wish I could have touched on Bayesian thinking) with a question: is it statistics that need to be confirmed by observation, or the other way around?

  • http://mapleleafshotstove.com/ daveybolland

    All perfectly valid points about error in human observation and memory.
    Thank you for mentioning the flip side of the coin – the overapplication of or overreliance on imperfect statistics can also be erroneous. I hope this is a two parter so as to point out those in more detail.
    With many of the advanced stats we are basically coming back to shots and pumping them into a formula. We’ve heard many convoluted ways of saying the Leafs were a poor team because they were outshot by 2.5 shots on average, or whatever it is.
    On its own I don’t think this accurately encaptures how the team played last season. Their system fit the strengths and weaknesses of the roster. I don’t think Cronin said anything terribly controversial and was surprised to see the interview get the reaction it got. Of course the goal is to generate quality possessions of the puck and Cronin said he wants the team to get better at it.

    • B_Leaf

      @daveybolland 
      Cronin’s points were legit. The Leafs rarely gave up good scoring chances. Even when some teams hemmed them in they were only perimeter chances if any at all. The best chances team generated against us consistently were point shots, and generally they had to hope for a bounce or a deflection. This is an aspect we need to improve on. But offensively not only did we create great chances at the other end, not only did we win the dirty ice, we also showed tremendous finishing skills because we had good finishers like JVR, Lupul, Kadri, Kessel, Frattin, Grabovski, MacA, Bozak, Kulemin. This year we have replaced a few guys with Clarkson and Bolland. In addition Gardiner should add offense from the back end. 
      If we can score the same way, while taking away the points better, we should be good.

      • http://mapleleafshotstove.com/ daveybolland

        B_Leaf I had no idea it was so controversial to dispute the idea that all shots were created equal.

        • NotInsane

          @daveybolland B_Leaf 
          Agree Daveybolland, the reliance on normally distributed shot quality is as erroneous as believing stock returns are normally distributed random events.

      • NotInsane

        B_Leaf 
        the Leafs had some great finish; none more so than Bozak who was perhaps the most dangerous Leaf on breakaways.

  • Doorman

    Third!!!

    • Burtonboy

      Doorman Better then last lol

    • http://mapleleafshotstove.com/ Radar O’Rielly

      Doorman Old man take a look at yourself, I’m a lot like you.

      • Doorman

        Radar O’Rielly Doorman 24 and there is so much more!!!  lol

        • wiski

          Doorman Radar O’Rielly sounds like time for a beer run 😉

        • Doorman

          wiski Doorman Radar O’Rielly Im Good!!!  lol

        • http://mapleleafshotstove.com/ Radar O’Rielly

          wiski Doorman Radar O’Rielly HooooooHaaaa!

          http://www.youtube.com/watch?v=rmcJWPYcr1I

  • Komas Taberle

    Alec have you applied for a press pass from Leaf media relations, if not you have now.

  • wiski

    https://twitter.com/RealBillWattershttps://twitter.com/RealBillWatters/status/359713782777380865
    Gunnarsson signing is money extraordinarily well spent.he eats up significant minutes.rreliable defensivelyq and solid on Special teams https://twitter.com/search?q=%23TML&src=hash

    • Komas Taberle

      wiski Bill is one of his moments of clarity before he gets his shit eating grin on and pisses all over his living room.

      • Doorman

        Komas Taberle wiski Lol.  Giving his dog some pointers!!!  lol

        • Komas Taberle

          Doorman Komas Taberle wiski lol

        • http://mapleleafshotstove.com/ Radar O’Rielly

          Doorman Komas Taberle wiski Or a bone….

    • Burtonboy

      wiskihttps://twitter.com/NormanJamesCTVhttps://twitter.com/NormanJamesCTV/status/359714508391989248
      https://twitter.com/RealBillWatters But Dave Nonis is a meathead, say the bloggers.

      • wiski

        Burtonboy wiski I’ve been away for the weekend but glad he signed at a reasonable price

      • SatsMundin

        Burtonboy wiski many of the people who give Nonis a hard time for his bad moves have credited him for this signing.. The people at PPP get harped on for always being so negative, but nobody will remeber moments like this where they had a positive reaction to the signing. Credit where it’s due for Nonis.

        • NotInsane

          SatsMundin Burtonboy wiski 
          PPP should take down the banner “Fire Nonis”.  I have no respect for them at this time.

  • NotInsane

    If you want to discuss Bayesian metrics discuss Bayesian metrics.  Every statistics should be evaluated individually rather than collectively.   Bu that’s just common sense.  Of course, everyone on this site can watch the same event and draw different conclusions.  
    We all use statistics.  Save percentage, goals, assists, ATOI: these are statistics. I don’t understand where this article is going except to challenge the “straw man” argument we don’t need any statistics at all.

    • http://mapleleafshotstove.com/ daveybolland

      NotInsane Also a good point.
      Those being painted as anti-statistics are basically just anti corsi/fenwick, not necessarily against using numbers.
      Also we have to be willing to admit “advanced statistics” have brought useful things. Like measuring zone starts, that’s an interesting piece of information. Usage statistics are very handy.

      • NotInsane

        @daveybolland NotInsane 
        Yes!  I agree completely.  I think there are many great “advanced stats” that show you the role a player has been playing in.  These are very helpful in understanding how a player contributes (or has contributed in the past).  
        Using Corsi to evaluate a player’s ability relies on the correlation between shots for/against and goals for/against.  I haven’t seen any convincing evidence that shots are a good proxy for goals.

  • http://mapleleafshotstove.com/ daveybolland

    TheCanucksnaphook Some but not all.
    Stephen Burtch strikes me as a bright guy who has tried to use his intelligent math brain to understand a game he has very little feel for. He wants their to be a number explaining everything that occurs on the ice and it’s just not a sport that lends itself to that.

    • MaxwellHowe

      @daveybolland TheCanucksnaphook Whilst I do not enjoy raising the spectre of game 7 once more, it does illustrate the weakness with stats.  Advanced stats do not explain how the Leafs could so thoroughly collapse and the Bruins could so thoroughly dominate in the closing minutes.  It was about momentum, experience, exhaustion and luck.  Stats do not measure these things.

      • NotInsane

        MaxwellHowe TheCanucksnaphook 
        So much of sport comes down to a few seconds and a fraction of an inch.  Its hard to imagine a metric that could capture the final two minutes of game 7

      • SteveBurtch

        MaxwellHowe TheCanucksnaphook But I thought you guys understood things like “random bounces”?
        Strange that your “feel for the game” CAN explain something that has basically never happened before, but “random chance” doesn’t work for you?

      • Dink

        SteveBurtch MaxwellHowe TheCanucksnaphook Mogilny  took a shot once, came up into stands and hit me in the crotch…thought that was kinna random.

  • Doorman

    Now there is a great handle name!!!  Mr. Rooter!!!  lol

  • SatsMundin

    TheCanucksnaphook ok, so let’s just throw out the idea of stats altogether then!! just because you (possibly incorrectly) believe a few people who use stats don’t know hockey well is no reason to disregard them completely.  As Taylor said, stats should not be the be all end all, and should be accompanied by analysis through watching the game, and vice versa.

    • Leafbites

      TheCanucksnaphook SatsMundin Simple as links golf.

    • Doorman

      TheCanucksnaphook Leafbites You got that wind mill hole figured out yet???  Lol

    • Uncle Otis

      Doorman 
      Nope,but he hits the clown’s mouth every time :)

  • wiski

    https://twitter.com/FarAndWidehttps://twitter.com/FarAndWide/status/359715036509384705
    RT https://twitter.com/BBC BREAKING: First https://twitter.com/search?q=%23royalbaby&src=hash photo released! http://t.co/aW1XwsCjed

    • wiski

      TheCanucksnaphook wiski LOL

    • dlb eh

      wiski 
      oh God no

    • dlb eh

      TheCanucksnaphook wiski 
      keep posting.  move this down the page fast.  it’s awful

    • Doorman

      wiski Looks like the Royal Milkman was at it again!!!  lol

    • Dink

      wiski looks like Brad Marchant !!

      • Uncle Otis

        @Dink 
        Clearly got Grandpa Charles genes 😉

    • http://mapleleafshotstove.com/ Radar O’Rielly

      wiski Shudder!

    • Komas Taberle

      wiski It does look like a Windsor.

    • http://mapleleafshotstove.com/ Radar O’Rielly

      wiski Wake up Maggie, there’s no fucking way this is mine!!!

    • http://i.imgur.com/MyKj5C3.gif ingy56

      wiski Fake….ears aren’t nearly big enough #Dumbo

  • mlclearwater

    Here’s a stat. There is one boring article posted above.  Lots of good work and arguments but dear god man. at least put some boob shots in somewhere

    • NotInsane

      TheCanucksnaphook mlclearwater 
      Cam Charron is perhaps the worst writer I have ever willingly read.

      • mlclearwater

        NotInsane TheCanucksnaphook mlclearwater Ya i dont mean to be rude and i appreciate the work but holy shit, just give me breast, trade rumors, player bio’s or some other shit I can enjoy. Stats are stats

    • Dink

      mlclearwater hahaha