Soccer Sabermetrics - Challenges

The Challenges of Soccer Sabermetrics

To continue on with my post from yesterday, talking about soccer sabermetrics, there's a few things to consider before I dig into the actual equations. I mentioned this briefly the previous post when I said:

Obviously the key difficulty is whereas measuring a single player's performance in baseball is relatively easy (each player performs, in essence, individually), it's harder to do for true team sports like soccer.

And I want to expand on that. In baseball, a batter performs on his own when he's hitting. Yes, he's reacting to the pitches, but it's his swing, his power, and his strategy that leads to hits or outs. The pitcher on the mound is relatively isolated as well. He works with the catcher, but the average catcher's efforts provide only a small amount of support to the overall effort.

That's not true on the soccer field. It's uncommon for a single player to act wholly on their own on the field, except, of course, the goalie, who is a special case (which we will deal with later). Absolutely, there are players who elevate the play of the whole team, and there are players, Lionel Messi for example, who can make fantastic plays on their own. But they're the exception and not the norm. But sabermetrics whole point is to calculate reliable non-biased statistics to measure individual players in their sport.

So two things need to happen:

1. We need to find a way to isolate an individual player's efforts from those of their peers.
2. We need to develop a set of statistics that indicate the overall ability of team as well.

Measuring the Individual Player

A good measure of an individual player's skill would be shooting efficiency. How many goals does a player make for every shot on goal? How many times do they have the ball stolen from them when they have possession? How many shots on goal does a player take over their total time of possession?

These types of statistics relate as closely as possible to what a single player can do on the field. Obviously most of these examples given are specific to offensive players, but they give the clearest picture of a player's contribution to the team. This is one of those challenging aspects of applying statistical models to individual players on a team sport. Relating it back to baseball again, leaving the whole DH vs. pitchers hitting discussion aside for now, every player plays offense, and every player plays defense. Not so in sports like soccer, American football, basketball, and so on.

Measuring the Team as a Whole

For overall team statistics? How long does the ball stay in a specific zone on the field? Does a team play 70% of their matches in the mid-field? Then maybe their forwards are underpowered. Do they play most of the match near their opponents goal? Maybe they've stacked most of their powerful players forward, and you need to adopt a strategy of long balls towards their goal.

The biggest concern in this class of statistics is that these can depend very heavily on the opponent. If you have an average team who faces four of the best teams in the league at the start of their season then the stats may be skewed unfairly in a negative direction.

Furthermore, as teams change, these statistics become invalid. Last year's "Total Defensive Power" may not apply when the keeper retires and the team sweeper gets traded. So each year you have to redo these numbers. Perhaps you could apply a modifier against the calculated number to reflect the number of personnel changes, but that seems like a poor practice right on the surface.

Handling the Challenges

Looking at these two classes of statistics, there are a few other problems which are apparent:

1. Not all players play in the same position all the time. You may have a player who moves around into several different positions. The statistics need to be tailored to the positions the player is in.
2. Not all players play the whole game. You may have a player who scores all of the goals in the first half and then needs to sit out the second. The statistics you generate should not be solely based on the overall outcome of the game, but zero in more tightly on the player themselves. Of course, if you have a player who routinely loses possession of the ball which leads to more losses, you should probably have a way to track that as well.

Unfortunately, or maybe the better word is realistically, this effort is a first draft. These methods and algorithms will be honed over time. I think it's better to keep them simplistic this first go round. The more complex they are, the more likely they are to have errors or biases we want to avoid. But as we apply the methods over time we will start see what needs tweaked where.

Alright, now I think we're ready to start talking actual algorithms.

Soccer Sabermetrics

I've been thinking a lot lately about how to apply the principles of sabermetrics to soccer. For those who don't know, sabermetrics is a set of advanced statistics computed against a player's performance in baseball. Starting in the 1980's, a scattered group of dedicated baseball fans realized that traditional baseball statistics, like ERA and batting average are not good measures of a player's true performance on the field. So they came up with new statistical methods which gave a more accurate picture of how valuable a player is in a game.

One such example is On-Base Percentage plus Slugging (OPS). Traditionally, a player's offensive abilities is measured through batting average. However, a player's BA is measured as their hits divided by their at-bats. Hits are not the only way a player can get on base. Players can get on base by getting hit, or by getting walked. You may have a fearsome hitter who gets intentionally walked, resulting in a lower average, even though he's consistently making it to first base. (Insert your own crude joke here about balls, first base, and hitters.)

What happens when you start to measure players through sabermetrics is you find players who are undervalued by traditional thinking, but are highly valuable during the game. It was the application of sabermetrics that allowed the Oakland Athletics to win consecutive World Series championships with no-name players on a shoestring budget.

So with this high-level overview, you can start to see the appeal of sabermetrics, especially if they can be applied to another sport. It lets you see things in different way. You feel like Neo in the Matrix. You see the code underneath the game. Maybe a player that appears undersized on the field actually prevents twice as many goals against your team compared to the player who looks more robust. Maybe a player doesn't score ever but assists on every goal. She would be just as valuable up front during an attack as a player who makes the goals. The new insight lets you reasses your players and their abilities. As a geek and as a soccer coach, this appeals very deeply to me.

Obviously the key difficulty is whereas measuring a single player's performance in baseball is relatively easy (each player performs, in essence, individually), it's harder to do for true team sports like soccer.

But I have been putting some thought into how to do it, and I think I have some good equations to start with.

I will begin posting the equations here for discussion and refinement.

I hope you're willing to join me on this discussion.

Thanks!

The Maurice Reeves Rule for Food Substitutes

Having a wife who's diabetic and having weight issues of my own, I have often notion of "real food" versus "engineered food", or "food substitute."

By real food I mean genuine food you can identify, with products you can readily identify. For example, a steak and a salad is real food. You know where they both came from. Fruit salad is real food. A fried egg is real food.

Food substitutes are things like Muscle Milk, Luna Bars, those Cookie Diet cookies. They were engineered and created in a lab. You're not stocking a jar of soy protein isolate in your pantry.

And the whole notion of engineered foods bothers me a bit. I don't think people should eat it. It's not good for you, despite the claims. And here's how I think I can prove it, with a simple rule:

If after eating Food Substitute X, you are still craving Real Food Y, then Food Substitute X was not worth eating.

Let me give you a concrete example:

Who among you has eaten a steak dinner, with a salad and a baked potato and said "You know what would really go well with this? A Slim-Fast." I venture none of you. But how many of your food substitute eaters have dutifully drank your diet shakes and eaten your magic diet bars and a half-hour later, an hour later, sat there thinking "I WOULD KILL FOR A DONUT." I venture all of you.

And you know what? Most times, you probably end up caving, especially in times of stress, which in these modern times, feels like all the time. So what you've really done is increased the total number of calories you've eaten, felt guilty because you still cheated on your diet, and felt miserable because you ate something you didn't really enjoy.

I say, ditch the food substitutes. Eat the real food. Enjoy your steak, enjoy your bowl of pasta, and feel contented in knowing where your food came from, and how sated you really are.

(FYI - I have cross-posted this to my other blog: Healthy Kids PA, which is part of an effort to make school meals better, and to increase the amount of gym available to students.)

Travel Plans

Heather and I were talking today about travel plans, where we want to go, where we should go, what we should see. All of this assumes we've got the kids with us, and we're hoping to travel to all these places before they graduate:

Here's the preliminary list in no particular order:

• England
• Scotland
• Ireland
• Germany
• Iceland
• Mexico
• Patagonia
• Honduras (Roatan specifically)
• Japan
• India
• Canada
• Tahiti
• France
• Italy
• Tunisia
• Mombasa, and Kenya
• Zanzibar, and Tanzania

And domestically:

• Texas
• New Orleans
• The Carolina Low-Country
• The Badlands
• Seattle
• Portland, OR
• Northern California
• Boston
• Maine
• Hawaii

This is by no means an exhaustive list. But off the top of your head, what are we absolutely missing?

Foreign Cookbooks - Today, France!

In what I hope will be part of a longer series, I came across two cookbooks from France that are held in the same high-regard in France as our American classics are here.

If you remember, this was a question I posted last week when musing about how we hold several cookbooks in high esteem, and I wondered if they did this in other countries.

Here's what I've discovered so far:
There is a book called the Larousse Gastronomique, which I had heard of before and completely forgotten. It was first published in 1938 and clocks in 1087 pages. And to think, editors in the US were concerned about the size of Julia Child's first book. Ha. It is an encyclopedia of culinary terms mixed in with recipes. The original book was purely French food, but a newer edition includes cuisine from other countries as well.

The other book is The Encyclopedia of Practical Gastronomy and is now out of print, but Julia Child herself gushed about the book and its broad scope and witty writing. I'm going to see if I can find a copy somewhere for cheap. I can't read French, I can barely ask my way to the bathroom, but it's worth a go.

I guess I shouldn't be surprised that the French have an affection and reverence for the cookbooks like we do. Scratch that, I guess I shouldn't be surprised that we have an affection and reverence for cookbooks like the French do. Despite public grumbling to the contrary, we share so much in common with the French, and owe quite a bit to them as well, that we are in essence family. There's enough material in this subject alone for a wholly new post, so I'm going to save my thoughts on this for later.

As for more foreign cookbooks, I'm going to bug my mom about German cookbooks. I know she has a few stashed away, and maybe I'll get to take some pictures and learn more about them. There is one classic German cookbook for Americans that I know of, by Mimi Sheraton, that I'm frankly not fond of, but I couldn't tell you why. I need to stew on it for a while.

More later.

What Next?

Last night's Boeuf Bourguignon went well, though the meat was a little dry. I can't be sure if that was from its age or the cut, but I'm not going to sweat it. Cooking for me, as anxious as I get, is about experimentation, and being willing to make mistakes. It's not about being perfect, at least not at this level, because I'm not going to be perfect.

Beef will be dry, gravy will lump, the onions will burn, and I will have to throw them out and start over again.

I will say this, however, the sauce, the veggies, out of this world. I followed the recipe exactly, and used three cups of a four-year-old red Zinfandel from California which was somewhat dry, and a little sweet, and it made for a great base. I did not put in the mushrooms, per my wife's request, though I cooked them on the side and mixed them into my final dish.

So, tonight, I'm not cooking. Heather wants to make one of the kids' favorite dishes, and it does not come from the Julia Child cookbook, if you know what I'm saying, so it will be more pedestrian fare. I'm not complaining. The kids don't want to eat fancy food every day, my wife won't tolerate me taking over the kitchen, and I do have other things going on that require my attention, like a job, coaching, PTO, fixing up the house, etc. Though, how great would it be to just cook, without the whole, having to own a restaurant and never being home on the holidays bit.

Maybe I should be someone's housewife. I will willingly be someone's housewife if they want. I'll clean their house and cook their meals, and they just have to pay me what I make now and give me benefits. I'm absolutely down with that. You just have to fight my wife for me. Good luck. She throws a mean right hook.

But even if I was cooking tonight, I don't know that I'd be cracking open MtAoFC. It's a fabulous cookbook and I'm infatuated with it, but I'm also a huge fan of Chinese and Indian food. I'm dying to have some Chicken Tikka Masala. Like right now. Someone bring me some. Maybe I'll make that in a few days, or maybe I'll crank out some Chicken with Broccoli. The world's too wide and big and wonderful to drill down into a single cookbook for too long. I've got too many other things I want to fry...I mean try.

So, what's next?

Tonight: Boeuf Bourguignon!

We have an eye round roast that needs to be cooked today, so tonight, I'm making a Boeuf Bourguignon.

I have the Julia Child cookbook open and I'm planning out the cooking. I have learned that I need to prepare everything before I start, or I get stressed and rush. Cooking shouldn't be like that, so the first thing I'm going to do is go through the recipe and mark everything I need, including my pots and pans. The French call this a mise en place. The literal translation is "putting in place", but it really describes a method for preparing all of your individual pieces ahead of time into individual containers, measured and organized so the cooking is easier.

If you had a recipe that called for:

• Four cups of red wine
• Two bay leafs
• Two springs of parsley
• A tsp of thyme
• 1 lb of mushrooms, sliced

You would have your four cups of wine measured out already, a container for each spice (or one containing all of them mixed together, if they went in at the same time), and a bowl of your mushrooms. You do all of this before you really begin the process of applying heat to anything.

As a German, it appeals to me in the way I struggle to explain. The Germans have a common phrase "Alles in ordnung" which means "Everything's in order." You usually say it when someone asks you how you are. We say "Okay" or "Going well", but the Germans say "Alles in Ordnung." The Berliners will sometimes say "Alles in Butter," which means the same thing, but gives life a deliciously rich and fatty sense, no?

If you've ever been to Germany you know that order is very important. I think there's a tiny Teutonic taskmaster in my heart somewhere pacing the halls and snapping brisk instructions when things fall out of balance. "Säubern Sie das Haus!" "Waschen Sie die Teller! Schneiden Sie das Gemüse! Gießen Sie den Wein!" (He may be bossing me, but he's very polite about it.)

And so I go about trying to get everything ready ahead of time. For me, the mise en place is not just about getting the ingredients ready, it's not just about making sure I have all the right tools, it's also about preparing me, the chef. I need to be ready, so I'm putting myself in a place where I can cook.

Luckily, with this dish, I will be able to do large parts of it ahead of time. The onions can be stewed now, the mushrooms sauteed as well and put aside, so at 2.30 I can put in the roast and be, generally, stress-free about the whole affair.

I'll never be completely cool about cooking. Even dishes I breeze through worry me when I'm finishing them up. Are the bits uniform enough to be pleasing, is the sauce spiced enough without overpowering everything, are all the vegetables cooked just right? I feel much like an expectant father in the last minutes before serving.

Still, it should go okay.

I'll post pictures and thoughts tomorrow.