Sunday, 18 February 2018

NZMS Result Analysis - Liz Davidson

NZMS is in the process of implementing the SNZ system for online entry to swim meets. In this system, entry times are automatically populated from recent results, rather than allowing the swimmer to enter their own time. This is a change to our historical method, so we thought it would be interesting to compare estimated Entry times of swimming events against the actual Result times. In particular, we want to gain an insight into whether using the fastest recent result for an event is a better predictor of actual performance than the swimmer’s own estimate of their time.

Although there have only been two meets so far using the SNZ system, early indications are that this a more accurate prediction of the actual result time that the swimmer’s own estimate.

Below are a analytical tables and graphs comparing the Entry System to the Swimmer Estimate.

1.  Accuracy of Estimate Analysis

This looks at the accuracy of the Entry time against the Result time – how close was the estimate to the actual time

With the SNZ system, 46% of estimates were withink 2% of the actual time, compared with 37% of swimmer estimates. Overall 94% of estimates in the SNZ system were within 10% of the actual time, compared to 90% of swimmer estimates.

2.   Entry vs Result Analysis

Left graph indicates system entry results and the graph on the right indicates swimmer estimated results.

This shows the accuracy of the Entry time against the Result time. The grey line represents total accuracy, ie Entry time = Result time. R-squared is a statistical measure of how close the data are to the fitted regression line. The R-squared value for the SNZ system is closer to 1 (perfect fit) than the swimmer estimate.

3.  Further Analysis

The above table shows further analysis of the accuracy of the Entry Time estimate against the actual Result time.

Below is the link to the Tableau website if you would like to look at the results yourself.

It is worthwhile to note that the “Further Analysis” section on the website allows you to look at different factors, e.g. Age, Gender, Event etc

The above analysis has been compiled by Liz Davidson and we are really keen to here from our Masters Swimmers what your thoughts are on the topic and the Entry system.

You can comment below or email us confidentially:

Below is the link to the PDF File for this article if you would like to download it.

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