Six Weeks?

Last year, Ben Cronin wrote about the importance of the first six games of a football league season (link) in the context of positions at the end of the season.

Ben’s analysis of the English Premier League noted:

The winner of Premier League has been outside the top four after six games on only thee occasions since the 38 game season was introduced in 1995/96 – (Manchester United moved from 10th to 1st in 2002/03, Manchester City won the league despite being 7th after six games in 2013/14 and Chelsea moved from 8th to 1st in 2016/17).

I followed up on Ben’s work with a look at six European leagues for the 2018-2019 seasons. Teams’ points per game averages after six games (PPG6) were:

After the latest rounds in all of the leagues, the average points per game (PPGn) are:

I looked at teams’ current performance relative to their week 6 positions (Change6n):

Postscript

In the 2017-2018 seasons in the six European leagues, four were won by the team leading their respective tables at week 6. The two exceptions were: in the Bundesliga, Bayern were third in week 6, the leaders then, Dortmund, finished 4th (29 points behind Bayern); in Serie A, Juventus were second on goal difference to Napoli, by the end of the season Napoli had moved to 2nd and were 4 points adrift of Juventus.

#AFLW 2019

The 2019 AFLW season starts on Saturday with the opening game between Geelong and Collingwood (link to fixtures).

I have some data from last year’s regular season (link) curated as secondary data from the official AFLW web site (link).

Median Profiles

A Violin Plot created with BoxPlotR (link). (W1Q is the winning team, L1Q is the losing team).

Plot information

These data have given me an opportunity to postulate some naive priors about when points will be scored in the 2019 season. The probabilities per quarter are based upon game outcome so that the labels ‘winning’ and ‘losing’ relate to the game not the quarter.

Biologging



Squid boats anchored in Paita, a port city in northern Peru. Humboldt squid support a massive artisanal fishery in this region.

This post started with a Luke Bornn tweet (link). He shared a link to Rocio Joo and her colleagues’ (2019) paper, Navigating through the R packages for movement (link).

In the paper, Rocio and her colleagues review 57 packages in R that are used to process, analyse and visualise tracking data. They note:

The advent of miniaturized biologging devices has provided ecologists with unparalleled opportunities to record animal movement across scales,and led to the collection of ever-increasing quantities of tracking data

I thought this paper would provide some fascinating background insights for tracking in sport contexts. Their review focussed on tracking data that had “at least 2-dimensional coordinates (x, y) and a time index (t), and can be seen as the geometric representation (the trajectory) of an individual’s path”(2019:2). I was very interested in their report of combined accelerometry, magnetometry and GPS data pre-processing (2019:7).

The paper prompted me to look in more detail at Rocio’s work and to contemplate what sport might learn from ecologists. To my great delight, I found reference to her PhD thesis submitted at the University of Montpellier in December 2013 (link). The title was A behavioral ecology of fishermen: hidden stories from trajectory data in the Northern Humboldt Current System.

The abstract of the thesis starts with:


This work proposes an original contribution to the understanding of fishermen spatial behavior, based on the behavioral ecology and movement ecology paradigms. Through the analysis of Vessel Monitoring System (VMS) data, we characterized the spatial behavior of Peruvian anchovy fishermen at different scales: (1) the behavioral modes within fishing trips (i.e., searching, fishing and cruising); (2) the behavioral patterns among fishing trips; (3) the behavioral patterns by fishing season conditioned by ecosystem scenarios; and (4) the computation of maps of anchovy presence proxy from the spatial patterns of behavioral mode positions.

What struck me about the thesis and its applicability to sport was the reference to ‘behavioural modes‘ associated with the tracks. The thesis is available as a pdf. I have downloaded it to examine it in detail.

Discovering Rocio’s work reminded me of a thesis I found many years ago, that changed my thoughts about how to share research stories. It was written by Jeanne Favret-Saada and had the delightful title Deadly words : witchcraft in the Bocage (1980).

Thanks to Luke, Rocio met Jeanne in this post. Both underscore how important it is that we step outside our comfort zone to explore ideas that can contribute to our practice and the ways in which we theorise about that practice.

Photo Credit

Squid boats anchored in Paita (Allison Guy)

Postscript

Rocio and her colleagues’ (2018) have also published a recent paper (December) that looks at Metrics for describing dyadic movement (link).