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Statistics for Managers: A Continuum of AVB

I've been working on some statistics for managers, focused on shot volume and shot selection under certain managers. This time I look at the career of Andre Villas-Boas, compared to the managers who preceded and followed him at Chelsea and Tottenham.

Alex Livesey

Most fans did not know what to expect when Tottenham Hotspur sacked Andre Villas-Boas in December and replaced him with Tim Sherwood. What we know now is that the two are radically different managers, tactically. Villas-Boas' high-pressing system has been replaced by a more open defensive system, albeit one that still works a high defensive line at times. Sherwood has changed personnel, bringing Emmanuel Adebayor and Christian Eriksen back in from the cold. He has established his own version of the 4-4-2 formation which, while it should be distinguished from the "caveman" 4-4-2 it is often assocated with, nonetheless differs significantly from Villas-Boas' preferred 4-2-3-1.

My question is, does this show up in the statistics? How does it show up, statistically?

The statistics I'm most interested in are shooting statistics. Obviously managers can have effects that are felt statistically in various ways, from possession percentage to pass completion to offsides calls won. But since I've been working with shooting data and collected a nice database on shots taken and conceded, I'm interesting particularly in how the tactical and personnel choices of managers affect the number and type of shots their clubs attempt.

Shot_matrix_medium I introduced these statistics in my piece on manager sackings last week. The numbers I'm looking at are pretty simple. First, I'm considering the simple question of shot location. How many shots is the club taking from the "danger zone" in the center of the eighteen-yard box (zones 1-3 in the map on the right)? How many shots is the club taking from the wide areas of the box? How many from outside the box? I have found that almost all of the highest-quality chances are attempts from the danger zone, so I'm also looking not just as shot totals but also at the percentage of total shots taken from the danger zone.

I consider these numbers for both attack and defense.

Further, how a shot is assisted makes a major difference in its expected rate of conversion. Shots assisted by crosses are generally much more difficult to place on goal than shots assisted by other kinds of passes. Shots assisted by through-balls, on the other hand, are far better than normal shots taken from the same area. I mentioned that "almost all" of the best shots are taken from the danger zone—the exceptions are shots off through-balls from the wide areas of the box (zones 4 and 5), which are roughly as good as normal shots from the center of the box.

So I add two more stats, Cross% and Through-Ball%. Since the vast majority of shots off crosses are taken from the danger zone, Cross% is the percentage of shots from the danger zone assisted by crosses. TB% is the percentage of shots from zones 3-5 assisted by through-balls.

Finally, I have average shot quality. This is a rating of the average expected goals per shot.

Chelsea Before and After AVB

So here's the data. I list all the totals in per-match rates, to even out managers who have had more or less time as manager at Stamford Bridge. Here's the raw numbers for both attack and defense.

Attack xG DZ SiB DZ SiBoT W SiB W SiBoT SoB SoBoT %Cross %TB %DZ Shot Qual
Ancelotti 1.79 7.58 2.92 3.29 1.13 8.53 2.37 49.0% 9.3% 39.1% 0.093
Villas-Boas 1.51 5.78 2.59 3.44 1.33 8.85 2.44 57.1% 9.7% 32.0% 0.078
Di Matteo 1.42 5.87 2.57 2.17 0.78 7.35 1.83 44.4% 8.9% 38.1% 0.089
Benítez 1.46 6.27 2.50 2.54 0.96 8.08 1.77 33.1% 5.2% 37.1% 0.087
Mourinho 1.47 6.00 2.30 2.45 0.90 7.10 2.20 47.5% 3.5% 38.6% 0.092

The first thing that stands out, I think, is just how superior the 2010-2011 Chelsea attack under Carlo Ancelotti was to those that  have come after it. Obviously personnel makes a big difference here, and Villas-Boas was originally brought in to manage the transition to a new, younger squad. But that is a huge drop in attacking production in just a single season.

You also can note the rate of shots taken from the danger zone and shot quality. AVB stands out significantly here. This will be a continued theme with Villas-Boas as we look at his time with Spurs. He does not care much for maximizing the number of shots taken from dangerous areas, and he likes his teams to shoot freely from deep areas. This leads to his Chelsea taking more shots from outside the box than Ancelotti's, even while average two fewer danger zone shots per match.

AVB's very high rate of shots off crosses is peculiar to me, and it did not continue at Spurs. The more striking number here is Rafael Benítez' extremely low percentage of shots assisted by crosses. He had his team playing through the middle to a much greater degree than did Di Matteo before him or Mourinho after him.

To give some context to these numbers, I've also got league-adjusted numbers. These are in the style of the Team+, Att+ and Def- numbers I use in my power rankings. If I have a manager with 110 under DZ SiB, that means his club took about 10% more shots from the danger zone than the average side in the league. If I have a a manager with 76 %Cross, that means his club took about 24% fewer of their shots from the danger zone off crosses than the usual side.

Attack xG DZ SiB DZ SiBoT W SiB W SiBoT SoB SoBoT %Cross %TB %DZ Shot Qual
Ancelotti 142 136 139 131 137 134 143 103 122 101 104
Villas-Boas 122 108 123 138 154 139 146 121 142 85 90
Di Matteo 115 110 120 89 90 118 114 97 132 100 102
Benitez 119 118 116 107 109 133 114 74 80 96 99
Mourinho 123 116 115 110 105 109 124 100 63 104 108

These numbers emphasize again just how much better Ancelotti's attack was compared to those who followed, as well as AVB's preference for high volumes of longer, lower-quality shots. The huge drop in shots off through-balls with Benitez' take-over and continuing through Mourinho, that I do not have an explanation for. It's interesting.

And now here are the same numbers, first raw and then league-adjusted, for defense under these five managers.

Defense xG DZ SiB DZ SiBoT W SiB W SiBoT SoB SoBoT %Cross %TB %DZ Shot Qual
Ancelotti 0.83 3.87 1.42 1.82 0.55 5.87 1.55 52.4% 6.2% 33.5% 0.073
Villas-Boas 0.93 3.81 1.56 2.26 0.78 4.81 1.44 52.4% 5.6% 35.0% 0.082
Di Matteo 1.11 4.43 1.91 2.65 0.70 5.96 1.65 52.0% 5.0% 34.0% 0.083
Benitez 0.97 4.08 1.65 2.58 1.19 5.31 1.62 50.0% 11.2% 34.1% 0.079
Mourinho 0.90 4.10 1.70 1.45 0.75 4.30 0.70 46.3% 5.1% 41.6% 0.090

Since managers can't directly tell opposition players when, where and how to shoot, you find fewer clear effects in the defensive numbers. It is again clear how much better Chelsea's defense was under Ancelotti. Di Matteo's reign stands out, in the league at least, as the weakest period of Chelsea's recent run. Benítez maintained a similar attacking quality while shoring up the defense, and these numbers suggest his interventions were critical in Chelsea achieving their third-place finish last year.

Defense xG DZ SiB DZ SiBoT W SiB W SiBoT SoB SoBoT %Cross %TB %DZ Shot Qual
Ancelotti 66 69 68 72 67 92 94 110 81 87 82
Villas-Boas 75 71 74 91 90 76 86 111 82 93 94
Di Matteo 90 83 90 109 80 96 103 113 75 89 95
Benitez 79 77 77 108 135 87 104 112 170 88 89
Mourinho 76 80 85 65 87 66 39 97 91 112 105

The other thing that stands out, here, is how Benítez and Mourinho have achieved very similar defensive results through very different methods. Benítez' clubs allowed opponents to take more shots from low-quality positions, but left themselves open to crosses and through-balls. Mourinho's defense has limited shots from outside the area to exceptionally low rates, but allows relatively more good shots from central areas.

I had expected to find AVB's Chelsea allowing tons of shots off through-balls, given the complaints about his high line. We do see such an effect with Spurs. I don't know if the issue here is simply a sample sample size (shots off through-balls are pretty rare) or if AVB was making adjustments to prevent through-balls.

Tottenham Hotspur Managers and Statistics

I want to make one thing clear before presenting these tables. Tim Sherwood has only been manager for four matches. Just about anything can happen in four matches. At one point last season Reading took ten points from four matches.

But, that said, Spurs have not been good overall under Sherwood's reign. They played Manchester United and Southampton roughly even away, but took six points. They deserved to lose to West Bromwich Albion and hung on for  a point. The Stoke City match rates as a high-quality stomping, but that's just one out of four. If Sherwood's Spurs are going to continue taking points at anything near this rate, they will need to play a lot better.

But starting with attacking numbers. I'll just post both tables, raw and league-adjusted, back-to-back. For Harry Redknapp, I'm just listing his club's 2011-2012 numbers, not his numbers from the previous seasons.

Attack xG DZ SiB DZ SiBoT W SiB W SiBoT SoB SoBoT %Cross %TB %DZ Shot Qual
Redknapp 1.58 6.50 2.45 3.11 1.00 8.71 2.55 39.7% 9.6% 35.5% 0.086
Villas-Boas 1.43 5.28 2.06 2.83 1.17 9.61 3.04 42.8% 8.7% 29.8% 0.078
Sherwood 1.19 5.25 1.75 3.50 0.75 6.50 1.50 52.4% 3.2% 34.4% 0.089

Attack xG DZ SiB DZ SiBoT W SiB W SiBoT SoB SoBoT %Cross %TB %DZ Shot Qual
Redknapp 127 121 116 125 116 137 153 84 140 94 99
Villas-Boas 117 100 97 121 133 155 188 93 143 78 89
Sherwood 99 102 87 157 87 100 84 110 58 93 105

You can see here again AVB's predilection for long shots. Even taking over a club which had generally not focused on emphasizing shot quality, he still cut the club's percentage on shots from the danger zone from 5% below league average to 20% below. Shot quality dropped from about average to 10% below. You can see also some of the progressivity of Redknapp's system. Running around a bit led to relatively few shots off crosses and quite a few through-balls.

So far, with Sherwood, we see a somewhat different profile. He's got the club taking more shots from better areas, though they can't seem to put any on target. The "cross" number may be inflated by the insane stats of the West Bromwich Albion match, and could go down over time. Really, all of Sherwood's numbers here should be taken as a snapshot rather than as a projection. The more interesting data is on Redknapp and AVB, for whom we have something approaching a useful sample size.

And defense:

Defense xG DZ SiB DZ SiBoT W SiB W SiBoT SoB SoBoT %Cross %TB %DZ Shot Qual
Redknapp 1.12 4.89 1.84 1.82 0.58 5.47 1.74 46.2% 6.3% 40.2% 0.093
Villas-Boas 0.95 4.09 1.85 1.80 0.76 4.07 0.96 44.3% 10.8% 41.1% 0.092
Sherwood 1.21 4.25 2.00 1.50 1.00 3.25 1.00 41.2% 16.7% 47.2% 0.126

Defense xG DZ SiB DZ SiBoT W SiB W SiBoT SoB SoBoT %Cross %TB %DZ Shot Qual
Redknapp 90 91 88 73 67 86 104 98 92 107 107
Villas-Boas 78 78 88 77 87 66 60 96 177 108 105
Sherwood 101 82 100 67 116 50 56 86 299 127 148

I think it's also useful to compare the xG numbers for AVB and Redknapp. They come out with nearly identical xG differences (+0.46 and +0.48), but Redknapp's numbers came from excellent attacking and good defending, while AVB's reversed that formula.

You can also see the effect of Villas-Boas' high pressing and high line in great relief here. AVB's clubs prevented shots of all types with their defensive pressure, but they could be cut open with a well-timed through-pass much more often than the typical club. The balance added up to an excellent defensive performance, but one shaped quite differently from those seen in the above Chelsea stats.

I argued after AVB's sacking that the breakdown in the club's defense in the last few months may have presaged his fall. So far with Sherwood we've seen only worse defense, and one even more open to giving up high-quality shots in the danger zone. Again, one hopes that this is improving, that it's only been four matches, but the early returns are less than encouraging.