Median of Medians as a Measure of Improvement for Lawn Bowls Practice

What one does not measure one does not consistently improve. This is because without measurement there is no feedback to quantitatively identify better versus worse performance. For measuring the accuracy of draw shots in lawn bowls several methods have been suggested.

 http://www.suncitylawnbowls.com/files/judson_accuracy.pdf

I am working on a method that should minimize the amount of measuring that needs to be done and so is the quickest way to integrate quantitative measurements into regular practice. Three bowls are thrown, one after the other, towards a position marked by a tennis ball or other small object. Several of these balls can be set out at different distances in both directions on the rink. The position of each tennis ball is marked on the green with a chalk X so it can be returned to the same position if displaced. After the three bowls have been grassed only the bowl 2^nd closest to the target has its distance from the jack recorded. A target at a different length is then selected for the three bowls going back down the rink in the other direction. Again one takes the measurement for the middle (median) bowl. After bowling an odd number of ends and collecting an odd number of distances, the set of lengths is ordered and the middle one is identified from this set. This is the median of medians distance from the target that you have bowled. The object is to improve this number with practice and experience.

What do you do if two bowls collide? Nothing -it is just as likely that the collision improves your median length as deteriorates it. If you can improve your scoring by promoting your bowls this should be measured as an improvement.

You might ask what do I do with my fourth bowl when performing this test. I direct mine at one of the alternate targets after I have thrown my three test bowls. Choose this new target to minimize any possibility of colliding with your test bowls.

Over time this measure should give a pretty good indication of whether you are improving or just maintaining the status quo.