The AFL season to date has chucked up a number of surprises, but now a pattern is starting to form. Indeed, it looks like a stratification between the top half and bottom half of the league has occurred:
The largest quality gap, aside from how far adrift Essendon are at the bottom, is the 4.6% drop off between 9th Port Adelaide and 10th Melbourne. Taken together, the drop between North Melbourne in 8th (104.8%) and St Kilda in 11th (95.5%) is larger than the space between top-rated Geelong and 8th-rated North Melbourne. Illustrated another way, we can see a pretty clear step down from the top 8 sides with only Port Adelaide threatening to bridge the gap:
Confronted with this data, we must ask, can the gap be bridged in the remainder of the season? How much ground can a team make up in these ratings over a three or six week period? It should be borne in mind that as the sample of games grows larger, each subsequent round contributes less to the overall rating of each team, so movements become less dramatic. This week for example only two pairs of teams actually changed positions:
For the purposes of making finals, North Melbourne is obviously an unrealistic target for the 9th placed Port, as they have all but ensured their participation in September by virtue of making the most of their soft opening schedule. It is more realistic that they might target Hawthorn, West Coast and Adelaide who are each a few rungs (and wins) lower on the ladder, each effectively two wins ahead of Port. The gap in rated strength between Port and these sides are even larger, and places Port in a no-man’s land that suggests they need those sides to deteriorate in form.
On the other hand, when we look at movements among these sides over recent weeks, there may be cause for hope for Port Adelaide:
The above table compares the current strength ratings to the end of round 5 and the end of round 8, showing form in three and six week intervals. Along with Adelaide and North’s improvement, Port shows as one of the strongest risers over the second quarter of the season. Hawthorn in particular has been fairly stable over that period. If this trajectory were to continue, Port Adelaide might have a chance to catch one of these sides.
The news is less good for Melbourne whose form has decayed slightly over this period. While much has been written about the Dees’ inconsistency, nothing here suggests they’re likely to make up three games on any of the most vulnerable top 8 sides.
Finally, we can examine these formlines for each individual strength indicator to see where the improvements have come from:
North Melbourne and Adelaide, earlier rated as having very strong forward lines and weaker midfields, have started winning a larger share of the inside-50s in their more recent games, providing their strong forward lines with more opportunity. North’s midfield has risen to average, while the Crows’ is now clearly above average in providing supply to their league’s best forward line.
By contrast GWS have recently been much worse at dominating the inside-50s than they were earlier in the season, which may be indicating their stronger recent opponents or a shift in their form.
In terms of forward line form, Carlton and St Kilda have recently begun producing more scores per inside-50 over the last 6 weeks and particularly in the last 3.
Sydney’s defence against scores per inside-50s has risen dramatically over the last 3 weeks thanks to strong performances against Hawthorn and North Melbourne, where their ability to prevent scores from opposition inside-50s pretty directly saved them in both games (note above that Sydney’s midfield strength form has deteriorated over the same period). Port Adelaide’s improvement over the last 6 weeks has also been very strong.
Among quality sides, Geelong presents as a team whose recent defensive form has let them down while the Crows, despite their overall gains, have slipped a little in defence as well.