Are AFL Scores Like Snowflakes?

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Last weekend while following the progress of a game I was struck by an odd thought: have two games ever had the same scoreline at the end of every quarter?

In other words, for example, has there ever been another game like the Melbourne v Kangaroos match where the scoreline went {3.0, 6.0, 8.4, 10.6} for the end of quarter scores for one team, and {4.5, 7.8, 14.12, 15.17} for the other?

The answer for the Dees v Roos game - at least based on the data I have - is no.

Actually, it turns out, the answer for all 14,490 games is the same. For all of VFL/AFL history so far, every scoreline has been unique.

What if we lower the bar a little and ask if there's been any pair of games where the scores have coincided for the first three quarters, but not the fourth. The answer is no again. So, in the same way as we could uniquely identify any VFL/AFL game ever played on the basis of the scores at the end of all four quarters, we could equally use just the scores at the end of the first three quarters for the same purpose. We might then think of the six base-pairs of numbers that represent the goals and behinds scored by each team at the end of the first three quarters as that game's unique DNA - or as a liniment-soaked snowflake if you prefer.

Only when we restrict ourselves to the scores for the first two quarters of a game do we finally find clones. Even then we find only 64 pairs of matched scorelines including, for example, a scoreline of {6.5, 8.10} plays {3.3, 6.3}, which appeared both in the Round 2 game between Melbourne and North Melbourne in 1995, and also in the Round 11 game between the Brisbane Bears and Sydney in 1987. No scoreline for the first two quarters has appeared more often than twice.

If we focus solely on the first base-pair, we find 1,557 quarter-time scorelines that have been repeated, five of which have occurred on 50 or more occasions:

  • {2.4} v {2.3} - 65 times
  • {2.3} v {2.2} - 58 times
  • {3.2} v {2.2} - 55 times
  • {3.3} v {2.1} - 52 times
  • {4.3} v {3.3} - 50 times

The most recent 2.4 to 2.3 scoreline at quarter time occurred in the very first game of the current season in which Collingwood led Fremantle by that score.

There have also been 730 quarter-time scorelines that have appeared only once, a few of which that caught my eye were:

  • 1940 Round 10 - Melbourne 9.6 vs Geelong 7.2 (finished as a 24.10 to 22.19 victory for the Cats)
  • 1951 Round 11 - South Melbourne 0.1 vs Carlton 1.10 (finished a 7.14 to 7.9 Blues win)
  • 1968 Round 7 - Geelong 4.13 vs Fitzroy 0.0 (finished 11.21 to 7.6 in favour of the Cats)
  • 1974 Round 21 - Richmond 10.1 vs South Melbourne 2.10  (ended as a 23.24 to 17.27 Tigers victory)
  • 2011 Round 6 - Essendon 15.4 vs Gold Coast 0.1 (ultimately a 31.11 to 8.10 victory for the Dons)

Since only 730 are unique, that means 13,760 are not. As we'd expect, quarter time scorelines are far less often unique than are scores for the first two and, certainly, the first three and all four quarters.

COMMON SCORELINES AT THE END OF EACH QUARTER

We've just looked at the most common scorelines at end of the first quarter, so let's next look at those that are most common at half time (ignoring their similarity or otherwise at quarter-time).

Only seven scorelines have appeared on more than 15 occasions:

  • {6.6} v {6.5} - 19 times
  • {5.6} v {5.4} - 17 times
  • {6.7} v {6.6} - 17 times
  • {6.7} v {5.6} - 17 times
  • {4.6} v {4.4} - 16 times
  • {5.8} v {5.6} - 16 times
  • {7.6} v {7.5} - 16 times

Exactly 3,319 games (or about one quarter) have produced a unique half-time scoreline. Again I'll highlight just a few that attracted my attention:

  • 1899 Sectional Round 3 - Geelong 13.13 vs St Kilda 0.1 (St Kilda didn't trouble the scorers in the second half, eventually losing 23.24 to 0.1)
  • 1934 Round 17 - Geelong 9.20 vs Essendon 1.2 (Geelong kicked 12.11 in the second half to win 21.31 to 6.5)
  • 1985 Round 2 - St Kilda 0.11 vs Carlton 10.11 (St Kilda never did find its range and wound up losing 2.17 to 25.19)
  • 1985 Round 2 (again) - Fitzroy 1.9 vs Essendon 12.11 (finished as a 24.22 to 8.15 Dons win)
  • 1995 Round 1 - Fitzroy 0.0 vs Essendon 7.12 (Fitzroy kicked just a single goal in the third term before piling on 5.1 in the last to run out losers 6.2 to 16.16)
  • 2004 Round 18 - Adelaide 0.10 vs Kangaroos 1.8 (both teams' accuracy improved only marginally in the second half with the Crows eventually winning 5.19 to 5.12)

How about three-quarter time scorelines?

Only five scorelines have appeared in 9 games or more:

  • {9.9} v {8.12} - 10 times
  • {12.11} v {7.8} - 9 times
  • {8.10} v {5.9} - 9 times
  • {9.10} v {6.8} - 9 times
  • {9.7} v {8.6} - 9 times

The last time we had a 9.9 to 8.12 scoreline at three-quarter time was in Round 16 of 2011 when the Tigers led the Dons by that score only to wind up losing 15.15 to 9.12. None of the four other scorelines in the list has appeared more recently than 2009, and the 9.10 to 6.8 scoreline has been absent since 1958.

Just under one-half of all games (6,827 of 14,490) have produced a unique scoreline at three-quarter time. To me, that's a surprisingly high proportion overall, but I'm not so surprised that the following scorelines have proven to be unique:

  • 1899 Round 3 - Essendon 0.7 vs South Melbourne 0.7 (ended as a Dons victory 1.9 to 0.9)
  • 1928 Round 6 - Geelong 15.7 vs Fitzroy 1.19 (ended 19.8 to 2.27)
  • 1947 Round 4 - North Melbourne 0.14 vs Fitzroy 14.21 (ended 4.15 to 19.26)
  • 1950 Round 1 - Hawthorn 1.11 vs Geelong 17.9 (ended 18.11 to 4.15)
  • 1979 Round 19 - Carlton 17.15 vs St Kilda 0.7 (ended 22.17 to 6.9)
  • 1993 Round 21 - Fitzroy 20.13 vs Brisbane Bears 1.5 (ended 22.15 to 5.13)

Finally, let's review full time scores where we find that only 14 scorelines have appeared 5 times or more.

  • {14.15} v {10.11} - 6 times
  • {10.10} v {10.9} - 5 times
  • {11.15} v {10.10} - 5 times
  • {10.10} v {9.13} - 5 times
  • {11.11} v {10.11} - 5 times
  • {10.14} v {10.13} - 5 times
  • {13.16} v {10.13} - 5 times
  • {10.14} v {9.7} - 5 times
  • {18.14} v {11.12} - 5 times
  • {18.12} v {11.13} - 5 times
  • {11.13} v {9.7} - 5 times
  • {15.11} v {14.12} - 5 times
  • {15.15} v {9.12} - 5 times
  • {8.13} v {7.8} - 5 times

Not since the 12th Round of 1970 when Geelong defeated Hawthorn by this scoreline have we had a 14.15 to 10.11 finish.

Roughly two-thirds of all contests (9,534 of 14,490) have produced a unique final scoreline. Some of the more unusual unique final scorelines have been:

  • Most Scoring Shots (91): 1974 Round 21 - Richmond 23.24 vs South Melbourne 17.27
  • Fewest Scoring Shots (13): 1898 Round 6 - South Melbourne 2.3 vs Melbourne 1.7
  • Most Behinds Single Team (41): 1977 Round 6 - Hawthorn 25.41 vs St Kilda 16.7
  • Highest Combined Accuracy (79.6%): 2009 Round 11 - Adelaide 21.4 vs Essendon 18.6
  • Lowest Combined Accuracy (5%): 1897 Round 9 - Geelong 1.9 vs Melbourne 0.10

SUMMARY

The uniqueness of VFL/AFL scores can be summarised as follows:

  • Every game played so far has been unique in terms of the scores of the two teams at the end of the first three quarters (and, consequently, at the end of all four quarters).
  • Only 64 scorelines for the two teams as at the end of Quarters 1 and 2 have been duplicated. That means about 99% of games have produced a unique scoreline for Quarters 1 and 2.
  • Only 730 games (or about 5%) have produced a unique scoreline at the end of the first quarter.
  • Exactly 3,319 games (or about 25%) have produced a unique half-time scoreline.
  • Exactly 6,827 games (or about 50%) have produced a unique three-quarter time scoreline.
  • Exactly 9,534 games (or about 66%) have produced a unique full time scoreline.

There is, in short, a great deal that's unique about the quarter-by-quarter scores of every AFL game.