Dwelling on dwell time

I have written two posts on dwell time this week. One on Clyde Street (link) and one for the Sports Wizard blog (link).

I have continued to research dwell time in non-sport contexts. The discovery of Herbert Levinson’s (1983) paper has been very influential in directing my literature searches.

In his paper, Herbert conducted an analysis of transit speeds, delays, and dwell times based on surveys conducted in a cross section of U.S. cities. He concluded that “reducing bus stops from eight to six per mile and dwell times from 20 to 15 sec would reduce travel times from 6 to 4.3 min/mile, a time saving greater than that which could be achieved by eliminating traffic congestion”. He added “transit performance should be improved by keeping the number of stopping places to a minimum”.

I have been thinking about how to visualise stoppages in play in sport. Two of the papers that cite Herbert’s paper offer some insights on how this might be done.

Robert Bertini and Ahmed El-Geneidy (2004) provided a case study of how this visualisation might occur with their estimation of “the values of parameters that affect the total travel time for a particular bus route in Portland, Oregon”. In doing so they shared a trip time model.

Their visualisation of dwell time included:

Mathew Berkow and his colleagues (2007) used colour in their visualisations of transportation in Portland:

Mathew and his colleagues conclude “On the basis of an analysis of 1 year of archived bus dis-patch system data for all routes and stops, the power of using visualization tools to understand the abundance of bus dis-patch system data is demonstrated. In addition, several statistical models are generated to demonstrate the power of statistical analysis in conveying valuable and new transit performance measures beyond what is currently generated at TriMet or in the transit industry in general. It is envisioned that systematic use of these new methods and transit performance measures can help TriMet and other transit agencies improve the quality and reliability of their service”.

These formative discussions about dwell time have really encouraged me to think about pedagogy in sport as well as officiating. In my next dwelling on dwell post I am going to look at referee behaviour at the 2018 FIFA World Cup and the 2019 Asian Cup. It is, I hope, the kind of detailed observation of performance that Herbert, Robert, Ahmed, Mathew and his colleagues might have found interesting.

Photo Credit

Photo by Scott Walsh on Unsplash

Opportunity

Tyre tracks on Mars from the Opportunity Rover.

Last week, NASA announced that “One of the most successful and enduring feats of interplanetary exploration, NASA’s Opportunity rover mission is at an end after almost 15 years exploring the surface of Mars and helping lay the groundwork for NASA’s return to the Red Planet”.

Opportunity landed on Mars on 24 January 2004. It was designed to last 90 Martian days and travel 1,000 metres. It exceeded its life expectancy by 60 times and traveled 45 kilometres. Its resting place on Mars is, by delightful serendipity, Perseverance Valley.

Opportunity’s history is a great metaphor many endeavours. Last week on hearing about the end of NASA’s contact with the rover, I thought about all those who have charted the world of performance in sport. The image of Opportunity’s tracks on Mars provide a great reminder of the tracks each of us follow in our own journeys of discovery.

Our tracks in analysing performance come from some very basic technologies and, in the case of some of the foundational ideas about performance, remain as relevant today as they were when they were first recorded.

Scoring first and not losing in association football

A bar chart of probabilities of scoring first and not losing in six European football leagues

After this week’s games in six European football leagues, it is interesting to see how each league is tracking against a prior probability of scoring first and not losing.

I established the priors from results in the 2017-2018 season. Two of the six leagues (Bundesliga and Eredivisie) are different to their priors in comparison to four other leagues (EPL, Ligue 1, Serie A and Primera).