Monday, January 4, 2010

Winter Break Review: Serie A

I'm going to try to go over each of the big leagues at this point discussing where we are and what should be expected going forward. I missed the Liga and will probably write that article at the halfway point. I will be giving my opinions more in these articles than usual but will still use the goal-differential and stats-based models.

Most Impressive

This is the easiest selection of any league. Inter have made the Serie A look like one of the small leagues that has one strong team. They are 8 points clear of their Milanesi rivals, who sit in second place with a match in hand, and 9 clear of Juventus. They are a ridiculous 13 goals better in goal differential than Juventus who are next best. It would take something major for Inter not to win at this stage.

Most Disappointing

I'm not sure where to go with this. To me the most disappointing club at the start of the season was Napoli, but they've done a good job of clawing their way back into the race for the European spots. Since Mazzarri took over they have a record of 5 wins and 5 draws, including a win at Juventus and draws against Milan and Parma. That's still not enough to challenge Inter, but it looks like they'll fight for Europe at least. I still wonder about their tactics. The board at Napoli seems to be quite fond of having just 3 backs as they have run a 3-4-3 or 3-5-2 with Reja, Donadoni and now Mazzarri. In my scoring model they rate as the 5th best team at scoring but only 14th best at stopping the other team from doing so. We're just short of halfway through the season so a lot can change, but it does seem like they have some defensive issues for a team challenging for a Champions League spot.

Milan are a similar story as they started out slowly but have since moved up to around where they should be. To be honest I'm not sure that there really is a standout team that fits the bill. Genoa and Fiorentina have slipped a bit but I think that's mostly just because the league is pretty tight after Inter. They are a short run of good results away from moving back up into the European spots.

Biggest Surprise

Again, it's tough to find one. Inter were expected to be better than the other contenders and they are. I'm a bit surprised that they are this much clear already, but it's far from shocking. There has definitely been some good football, but in terms of surprises or suspense as far as the results go, it's been on the boring side frankly.

Lucky (More Efficient?) Sides

Luck always plays a big role in sports results. It's not discussed enough in my view, which is why I try to write a lot about it. The models I use are a good way to look at which teams have gotten better or worse than average luck. The first way I measure it is comparing points and goal differential. One place where luck plays an important role is in the timing of goals. As I have argued, the number of points a team gets is based on two things: goal differential and variance. If a team has a lot of points compared to other teams with the same goal differential then they've been lucky and vice-versa. I make a slight adjustment to goal differential by using the goal-only model to account for differences in schedule.

The stats-based model can go a step further because it can also give an indication that a team has gotten lucky or unlucky when it comes to scoring and allowing goals. For example, a team may be consistently getting more shots than their opponent but have the opponent's keeper make a lot of great saves while giving up some goals on bad bounces at the other end. The stats model I believe to be very accurate in ranking the teams, though it is overly favorable to weaker sides.

Looking at goal differential and points, it is unsurprising that the teams that have been most unlucky are near the bottom of the table. The three with the worst luck are Catania (18th in the table), Lazio (16th) and Siena (20th). At the other end you have Milan, Parma and Sampdoria as the most fortunate. Looking at Milan, they are 3 goals behind Juve but have one point more. According to the model and the regression formula from this article, Milan are nearly 6 points above expectation for a team with their goal differential.

Digging a bit deeper, the biggest thing jumping out from the stats-based model are two teams that appear to have been quite unlucky: Lazio and ChievoVerona. Lazio rate as 9th best in the model but are 16th in the table, 17th if you go by points per match. They also are 15th in goal differential per match so it's not all about getting a lot of big wins and close losses as discussed in the previous paragraph. I'll write more about shots later, but both shots and shots-on-target are strong indicators of the strength of a team. Lazio are 6th best so far this season in shot differential per match and 9th best in shots-on-target differential. They have shot the ball an average of nearly 2 more times per match than their opponents and have the same number of shots on target as they've allowed. That doesn't sound like a team closer to the bottom of the table than the middle.

Since they have taken and allowed the same number of shots-on-target but have allowed 6 more goals than they've scored, it's clear that they have problems in front of goal at one or both ends of the pitch. The problem is 100% on the attacking end. Lazio rate dead last when it comes to converting shots-on-target into goals. They have taken 7.5 shots for every goal, a scoring rate of 13.3%*. For comparison, the league average is 3.58, or scoring on 28% of shots on target. In other words, they require more than twice the number of shots on target to get a goal as the league average. Defensively and in goal they are actually good. They have allowed the 4th lowest shooting percentage; their opponents have scored on just over 21% of their shots on target. I'm sure with numbers that bad they've been unlucky, but it seems clear that the Aquile need to get better showings out of Zarate, Rocchi and Cruz up top.

ChievoVerona also seem to be running well below expectation. The model rates them as the sixth best side, while they sit 12th in the table (13th if you go by points per match). They are 6th best in shot differential per match and 4th in shots-on-target differential. Given that, it's surprising that they find themselves in the bottom half of the table. While I don't think I've seen them play this season, the numbers indicate that they have had some combination of being unlucky at both ends in front of goal, not doing a good enough job of finishing and letting too many shots go in. Looking at goals per shot-on-target, they rate 15th best at converting shots into goals and 12th best when it comes to goals conceded per shot-on-target allowed. While not as extreme as Lazio, Chievo have probably not been good enough at converting chances and been a bit unlucky as well.

At the other end of the spectrum are Genoa and Palermo. Both are about 6 spots higher in the table than the model ranking. Genoa have been extremely efficient in front of goal, scoring on a higher percentage of their shots on target than any other club in the Serie A. They have scored on nearly 42% of their shots, about one and a half times the league average. Particularly impressive are Crespo up top with 4 goals on only 7 shots on target and in the midfield Mesto who has 4 goals on just 6 shots on target. I have nothing against the Genoa players, Crespo certainly was elite in his prime, but I'd say they have been fortunate to score as many goals as they have. I expect them to slow down. As for Palermo, I'm not really sure to what to attribute their position.


I'll make a few predictions and revisit them from time to time later in the season. A lot of these are pretty clear based on what I've written above.

Inter will run away with the league title. This prediction is coming in off a limb.

Juventus will jump over Milan. I don't think this is too crazy of a prediction either. Juve have looked better to me and both of my models agree. I think they are enough better to overcome the current deficit which is one point plus one match. I expect Juventus to be clear while Milan and Roma fight for the third automatic Champions League spot.

The four Champions League teams next year will be Inter, Juventus, Milan and Roma. Right now Parma are tied with Roma and there are 7 other teams within 4 points. I don't think any of those teams will jump into the top 4.

Bologna will get relegated, Catania will be safe. In each of these articles I'll pick a club that is out of the relegation zone to go down and one in the bottom three to stay up. My picks for the Serie A are Bologna to get the drop and Catania to stay clear. According to the stat-based model, Bologna rate as the worst team in the Serie A. Part of this is that they are last in both shot and shot-on-target differential. They have some decent, though past their prime, attacking talent but have surely been fortunate in that they have put away a high percentage of their chances. Of the three bottom teams, the model rates Catania the best at 15th. I expect them to be more stingy the rest of the season and get out of the relegation zone.

* This could be slightly off. I've never seen a definition of a shot on target so it's possible that you could have a goal without a shot. It seems likely that an own goal, especially the most embarrassing kind, would not be recorded as a shot. None the less, for simplicity of language I will define shooting percentage as goals per shots on target.

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