Behind The Numbers: Seasonal variations

This week our statistician Josh James looks at trends in Arsenal’s form throughout the Wenger era.

The clocks have gone back, the yellow ball is in play - so how do Arsenal traditionally fare during the winter months?

The yellow ball was introduced to the Premier League for season 2004/05, and is used between November and February. This acts as a nice definition for ‘winter football’ and so we can compare how well Arsenal perform at this time of year, as opposed to the rest of the season.

Last term Arsenal fared much better with the yellow ball than the regular white one, garnering 2.12 points per game from those 17 matches compared to 1.52 points per game for the rest of the season. Indeed in four of the past five seasons, the Gunners were more successful with the yellow ball.

However, looking at the seven complete seasons since 2004/05, Arsenal have been less successful during the winter (1.86 ppg) than the rest of the season (2 ppg). Not a huge difference, but there have been three seasons (2004/05, 2005/06 and 2008/09) when the team earned over half a point less on average during the winter months.

Arsenal also tend to be less prolific during the winter months, scoring 1.75 goals per game with the yellow, and 2.09 per game with the white. The biggest disparity came in 2008/09 - that season Arsenal didn’t score at all in the last four games with the yellow ball, then netted 20 in the next six games once the white ball returned.

We can break this down further, and assess which months of the year are most/least successful for Arsenal.

It’s long been said that Arsenal’s form suffers in November, and the stats would support this view. Arsène Wenger’s first ever defeat as Arsenal boss came on November 16, 1996 (1-0 away to Man United), and they lost at least twice in each subsequent November, until 2003/04 when they remained unbeaten through six games that month.

Then, two years later they won all six November fixtures, and in fact, if Arsenal win their next three matches, February will take over as the month with the lowest win percentage since Wenger became boss.

The most successful month for Arsenal during the Wenger era has been March (64.8 per cent win rate) - one of five months when the team’s win rate is well above the overall average (57.9 per cent).

Traditionally the team start well - the win percentage for each of the first three months of the season is well above 60 per cent. However the drop off in form during November and December means that the win percentage for the first half of the season (Aug to Dec) is almost identical to the second half of the season (Jan to May) - 57.7 per cent and 57.9 per cent respectively.

Of the 151 complete calendar months in which Arsenal have played senior matches under Wenger, they have recorded perfect records nine times, and failed to pick up any wins just twice (February 1997 and May 2007).

Looking purely at league football, some definite trends appear. Arsenal haven’t lost a March fixture since 2008, and have suffered only two defeats in January or February since 2006.

What’s clear from the stats though is that Arsène Wenger would dearly love to improve the late-season form, which was the hallmark of his early teams.

In his first nine seasons in charge, he lost only lost one league game played in the month of April. The March record was similarly impressive - just two defeats in that month between 1997 and 2006.

The May stats are slightly skewed by the number of ‘dead rubbers’ played in that month, when the final league position was already confirmed before the fixtures were played.

Incidentally the last time Arsenal played a league match in June was 1947, when the Gunners lost 2-1 at Sheffield United in the final game of the season. That remains the only time Arsenal have played a league match at any time other than August to May. Until after World War One the league season always kicked off in September.

So what could be the reasons behind the differences in form between the months?

One explanation could be the heavy schedule the team often endure during the winter months - December and January are the busiest months of the season. The most games Arsenal have played in a calendar month under Wenger is nine, on three occasions (December 2001, December 2007 and January 2011).

Maybe another reason could be the increased travelling at various times of the football calendar. The Champions League, and indeed international football, takes a hiatus between early December and mid-February, but analysing the results immediately after such engagements provides some surprising findings.

It’s often said that playing in the Champions League - especially away fixtures - can have an adverse affect on subsequent games, and indeed this season’s 8-2 defeat to Man United and 4-3 reverse at Blackburn came directly after trips to Udinese and Dortmund respectively.

But analysing the Club’s all-time Champions League record contradicts this view. Arsenal have played 71 domestic matches after returning from a Champions League away day, winning 42 (59.2 per cent) of them. That’s actually a better record than the Club’s overall win ratio (57.9 per cent) for the same period (1998/99 to present), meaning the team’s chances of winning improves after a European away game, not decreases.

Strangely, Arsenal even fare better after returning from an away Champions League game, than they do after a home Champions League game, as the table below shows.

But what about games that come off the back of an international break, a category that this weekend's trip to Norwich falls into?

Again the stats show that rather than a drop-off in form, results actually improve in such instances.
Arsenal are unbeaten in their last five matches immediately following a mid-season international break, and have won 27 of 43 (63 per cent) such fixtures since 2004/05. That’s higher than the overall win average for the same period.

The last time Arsenal lost on the resumption of domestic football was this time last season - a 3-2 home defeat to Tottenham. In fact that’s the only time Arsenal have lost a home fixture after an international round in the past eight seasons.

A note of caution going into this weekend’s match at Carrow Road though, Arsenal’s win percentage in these fixtures drops in away fixtures, winning seven of 17 (41 per cent) when having to hit the road on the resumption.

Josh James also provides the stats for the Arsenal Analysis pages of the matchday programme. To subscribe, or buy online, click here.