Netball, shoals of fish and visualising performance

Last Friday, I was in Dublin at #HPX17.

I had just heard Joe Schmidt open the conference. I was about to present an hour later so I edited my presentation after reflecting on some of Joe’s points.

I thought I would check my email feeds to see if anything else might need considering. An ABC article about Australian netball by Joel Werner and Jonathan Webb led me to tweet this:

I am instantly attracted to whatever Lisa Alexander (coach) and Mitch Mooney (analysts) do in netball but I did need to resist the temptation to delve with just 45 minutes before my presentation. I did add a link to the ABC article in one of my concluding slides and mentioned evolutionary algorithms as a one-liner for the audience’s consideration.

The title of my talk in Dublin was Performance Analysis and Data Analytics: Are We There Yet?

Almost a week later, I am back at the article. The day after Australia has taken a 3v0 lead against New Zealand in the Constellation Cup netball series.

The ABC article discusses Mitch’s interest in collective behaviour. I have had a long term interest in ethology and my posts have included discussions about starlings, sticklebacks, wildebeest, zebrasĀ and rhesus macaques.

Mitch’s use of a Voronoi visualisation caught my attention. (It appears as a gif in the ABC article.)

I am delighted Mitch and Lisa shared their thinking so openly. I am hopeful that this article might trigger lots of conversations about:

  • Ethological insights into performance
  • Coach analyst relationship
  • Visualising and sharing data

These issues are embedded in my single slide in Dublin. Now I have lots of time to unpack them.

Yesterday I was writing about the visualisation of boxing data. Today it is netball.

I am hopeful that both Matthew Sankey and Gregory Voronoi have a place in our sharing of stories.

Photo Credit

Coaches watch at the AIS (Teresa Tan, ABC)

Points Scored Profiles Prior To #NRLGF 2017

The Melbourne Storm have defeated the North Queensland Cowboys in the 2017 NRL Grand Final.

I have monitored scoring patterns in the NRL in 2017 and have used the official NRL web site as my source of secondary data.

I have used BoxPlotR to visualise the scoring profiles of the two teams in the Final.

In the plots, the centre lines show the medians; box limits indicate the 25th and 75th percentiles as determined by R software; whiskers extend 1.5 times the interquartile range from the 25th and 75th percentiles, outliers are represented by dots. There are 26 sample points.

Melbourne

North Queensland Cowboys

Melbourne and North Queensland Comparison (Points Scored)

… which led me to believe that Melbourne would win the Final by a margin of not less than 9 points. The game would be much less predictable if the Cowboys could score two tries in the first half and play above their season median profile after an exhausting series of games on the road.

Photo Credit

Winners (Liam Cox, Twitter)

Dogs, Tigers, Medians and Moments: Reflecting on the 2017 #AFLGF

Introduction

Richmond Tigers have won the 2017 AFL Grand Final. They defeated Adelaide by forty-eight points.

Two days ago, I used median scoring profiles to suggest, all other things being equal, an Adelaide win. My season’s data for the competition gave me these end of quarter scores:

In my post, I suggested that the challenges to an Adelaide victory were:

  • The closeness of the contest in the first quarter of the game
  • Whether Richmond stayed with Adelaide in the 2Q
  • If Richmond lifted in 3Q

Should Richmond mange these three conditions, I thought this would mean it would come down to which team had the legs and tactical nous in 4Q.

The scores by quarter were:

Richmond turned an 11 point deficit at the end of the first quarter into a nine point lead at half time. The end of the first quarter was the high water mark for Adelaide in the Final. Richmond outscored Adelaide in the second quarter by 20 points, lifted in the third quarter to outscore Adelaide by 25 points, and had the legs in the final quarter to outscore Adelaide by 14 points.

The Dog in the Night-Time

My all-things-being-equal-model indicated an Adelaide win. I was mindful that Richmond’s opportunities to own the game required some conditions to be met. I identified these conditions using median scoring profiles for each quarter of games played over the whole season for both teams.

The result of the game sent me back to a paper written by George Lewis and Jonathan Lewis in 1980, The Dog in the Night-Time: Negative Evidence in Social Research. They proposed:

In social research, there is an overwhelming emphasis upon collecting positive data, whether it be in the form of statistically significant attitudes, important documents, or observer descriptions of unique settings. This emphasis, while responsible for shedding much light in previously dark areas, none the less has had the important and dangerous side-effect of minimizing the worth of negative evidence, that is, the significance of a thing’s absence. (1980:544)

Their paper suggests a paradigm of seven types of negative evidence:

(1) Events Do Not Occur; (2) Population Is Not Aware of Events; (3)Population Wishes to Hide Events; (4) Commonplace Events Are Overlooked; (5) Effects of the Researcher’s Idea Set; (6) Unconscious Non-Reportage; and (7) Conscious Non-Reportage. (1980:544)

They conclude with the observation “in order to gain the best perspective on the problems one is studying, there must be a greater emphasis on uncoverlng and utlilzlng negatlve evidence” (1980:555).

Moments

This post is my way of responding to negative evidence and is an exploration of the phenomenographic reporting of the game. I did not watch the game but monitored the score on the AFL web site.

Moments in the Grand Final for me were:

Post game I looked at the official AFL match feed and picked out these moments:

This led me to think about the conversations both coaches would have had with their respective teams at half time. I felt that a nine point half-time difference would make the third quarter of the game a fascinating contest of wills and dynamical tactical responses.

Note the word ‘obliterated’ in this Q3 summary.

The outcome of these moments was Richmond’s first championship in 37 years. Now that this game is in the data base we have an opportunity to contemplate how the Final might have been played differently.

Moving from If …Then to Yes … And

I confess to not going out in my back yard to replay the moments of the Grand Final. I did imagine how these games might be played out in yards in Richmond and Adelaide.

What the negative evidence of this Grand Final has encouraged me to think about is how we might structure learning environments. I am more and more convinced that if we were to move away from prescriptive IF … THEN plans to a much more improvised YES … AND encouragement, we might be able to be even more responsive to changes in game state and tactical dispositions.

YES … AND accepts negative (and positive) behaviours and dampens (or amplifies) them. In my data terms, this would enable teams to be true to type in any game context … even with the aura of playing in a Grand Final.

Photo Credits

We’ve done it (Richmond FC, Twitter)

Well that was fun (Caitlin Arnold, Twitter)