With very minor exceptions the signing of Shkordan Mustafi, 2 days before deadline day, was met with the usual sensationalist delight by the mainstream media. Most reveled in Arsenal’s contribution to English football setting a new transfer record of £1.2b this past window.

In terms of footballing analysis most saw it simply as Wenger turning to Mustafi to ease his defensive crisis. According to Sky Sports:

The £35m fee is considerable. But it might just be money well spent. Mustafi has the quality to be a significant upgrade on Gabriel Paulista and with Mertesacker turning 32 this month, there’s a vacancy to be filled. 

Very few of the pundits seem to look beyond the price tag, Tom Adams of ESPN seemed unto something when he observed that:

In such lavish times, it is possible to miss the importance of a transfer fee even as high as the £35m Arsenal have reportedly paid for the 24-year-old Mustafi, who became the second signing of the most expensive day in Wenger’s career with the earlier capture of Spanish forward Lucas Perez for £17m making Arsenal’s total outlay on Tuesday a cool £52m. These are not the biggest deals of the summer by any means. Yet in particular, the signing of Mustafi from Valencia is hugely significant.

Yes the transfer is considerable based on the past five years of signings by Wenger:

The ESPN man did not need to be a rocket scientist when noting:

Over the past five years Not only is the German the joint second most expensive signing in Arsenal’s history, along with Alexis Sanchez and Granit Xhaka, he is also the most expensive defender Wenger has signed by some distance, his fee dwarfing the £16m paid for Calum Chambers two summers ago.

But then his analysis stopped short, restricting himself to the conclusion that:

It is … a riposte to the very vocal elements of the support who have demanded that Wenger spend some money. This summer, Wenger cannot be accused of going AWOL in the transfer market or treating the club’s vast resources like his last tranche of personal savings. The best part of £90m has been spent on new players. Arsenal have not stood to the side, holding their nose in disgust while other clubs have indulged in an orgy of greed; they have, belatedly, become willing participants.

We at PA cannot restrict ourselves to such trite analysis. As my investment advisers would warn, beware of cherry-picking of data “to reinforce emotional responses”.

Many of us are now increasingly aware that Wenger has been rebuilding a squad that can truly compete for the title. He has been ruthless and deliberate. Note that of the class of 2011-12, with the exception of Mertesacker and The Ox, none of the others have made the cut for 2016-17. They have either been sold, loaned or let go as their contract expired.  Meanwhile forwards, midfielders and goalkeeping positions have been reinforced by very capable, experienced players. Ozil, Sanchez and Cech are indisputably among the very best, to use that hackneyed phrase, world-class. Why therefore such a heavy expenditure on a defender?

The key can be found in the data from my last blog when I compared Wenger’s Highbury vs Emirate years.

Highbury Years

Contrary to current mythology, at Highbury we were never a rampant, free flowing goal-scoring machine. We only averaged 1.9 goals per game in 10 years under Wenger. In fact those seasons when we scored a relative avalanche of goals, 85 in 02-03 and 87 in 04-05, we failed to win the title. What was distinctive at the old ground was the meanness of our defending; averaging a measly .87 goals per game in those halcyon years. The most impressive year was in 98-99 when we allowed in a mere 17 goals for the season vs a paltry 59 GF, coming 2^nd. Boring old Arsenal, eh.

I am very struck by the fact that after conceding an economical 36 goals in 01-02, to win the title, Wenger and Dein latched unto Sol Campbell’s desire to free himself from the hell-hole at the Lane. The rest we all know is history. What is not as well-known is The Invincibles let in a measly 26 goals, an average of 0.68 per game. They only scored 73. Compare and contrast with the barren period that followed.

Emirate Years

Shock, shock, shock. The defending at Ashburton Grove is far from the high standards of Highbury, deteriorating by 18% between eras from an average 33 to 39 GA. Currently we are easily allowing in one goal per game compared to 0.87 at Highbury. In contrast goal scoring had a mere decline of 2.7% between eras. As a result average Goal Difference (GD) between eras fell from 38 to 32, a 15% deterioration.

After the club let in four goals at home vs Liverpool on the season-opener, is it any wonder Mustafi started vs Southhampton at the first opportunity. Now it makes sense Wenger decided that, despite a hefty £16 million investment in Callum Chambers, it was better to pack him off to Middleborough to complete his education. Obviously, like Sol Campbell, Mustafi is not only one for the future, he is for the present. In the words of Arsene:

“He is at the right age. He has good experience. He is a very focused player who can play with the ball as well. We have taken a great player but have prepared well for the future.”

Finally, let me remind you that in 07-08, when in my opinion we posed our last real challenge for the title, we let in a measly 31 goals for the season or 0.82 per game. So far after four games we are 6 GA or 1.5 per game. Clearly we have some ways off in getting anywhere close to 0.87 but it is still early days. But the data is compelling; lowering the GA is the key to why Mustafi could be our most important signing.