Leigh & Lowton PY Numbers 2013

 
Race data from our various handicap series has been input to the 
RYA website and their systems have analysed the data and produced
suggested PNs for classes at L&LSC.  Basically, the RYA compute 
the average corrected time for a race and then for each class 
within it. This shows what change in each class handicap would be 
needed for their average corrected times to all be the same. 
Poor performers (outside 20%) are automatically excluded before
class handicaps are computed by the RYA. That is intended to 
prevent undue influence from those who were late to the start, 
having a really bad day or simply new to the sport or the boat. 
Movements in class PNs are weighted so that a small the number 
of results for any class do not have an undue influence compared 
to those with large numbers of results.

After inputting all the data available, for all the series’ 
back to 2007 (currently 600 races with thousands of results), 
the RYA has produced a list of Leigh & Lowton specific 
Portsmouth Numbers – for all those classes with sufficient data 
available.

They have also give a confidence level. ‘Confidence Factor 
(c.f.)’ refers to the stability of the number – not its accuracy. 
Confidence in the stability of PNs obviously rises as more race
 data is input and as we are in the first year of this process 
we decided to recognise the likelihood of increasing confidence, 
and so the Sailing Committee has agreed that the changes 
recommended by the RYA for L&LSC will be ‘damped’ by applying a 
% adjustment. Depending on the confidence level the % of any 
change applied will be as follows

0.0 c.f. = 0 % RYA Number to be used,
0.1 c.f. = 20%,
0.2 c.f. = 40%,
0.3 c.f. = 60%,
0.4 c.f. = 80%,
0.5 c.f. = 100%

Below is the RYA 2013 List with the amendments for the 
LLSC 
PY numbers approved by the RYA: