Trial of Personal Handicap System for NHEBSC
What is a Personal Handicap?
A personal handicap is an adjustment to the standard boat’s Portsmouth Number, calculated to give everyone an equal chance of winning. If the personal handicap perfectly reflected your skill, and everyone sailed to their average skill level, the result would be everyone finishing first equal.
Applying a personal handicap across a series of races means that the winner will be the person who improves the most over their performances leading up to the series. Someone who is at or near the back of the fleet based on their actual skill level, could still win on personal handicap if they show the most improvement. At the other end of the fleet skill level, the sailor who is at the top of the fleet based on their actual skill level, could finish low down the results based on personal handicap. Indeed it is probably harder for the good helm to finish high up in the personal handicap results as it will probably be harder for them to make the same proportionate improvement as can be made by the relatively unskilled sailor.
A personal handicap is also a means to see how your performance compares and changes compared to others of similar skill. If your personal handicap reduces by 3 points and your competitor’s reduces by only 2 points then you have shown the most improvement.
How often does my Personal Handicap get updated?
There are two aspects to calculating a personal handicap:
1) A personal handicap is calculated for every race that is sailed as a handicap race, i.e. all boats start together and each boat is timed as it crosses the finish line. This personal handicap is the handicap you needed for that specific race such that everyone in the race would have had the same corrected time. [This corrected time is the actual finish time corrected for the combined boat and personal handicap.]
2) For a personal handicap based series result, a fixed personal handicap is used to process all the races in the series. This personal handicap is based on your performance up to the start of the series. It is an average of your individual race personal handicaps described in 1) above. Currently it is an average of your best 9 results out of your last 10 races. Your worst result is discarded so that a bad day does not distort what is a fair personal handicap.
Information on the personal handicap values for a series is available in the Personal Handicap Database spreadsheet on the website.
How is my Personal Handicap affected if I sail more than one class of boat?
Your skill may be very different when you sail a different class of boat. Personal handicaps are calculated for each class of boat sailed. So at the start of a series you may have multiple personal handicaps that are used as required, for example one for a standard Laser, one for a Laser Radial and one for a Solo. Each one will have been calculated based on your previous results in just that one class.
You also have an ‘All Classes’ personal handicap based on all classes you have sailed (in the last 10 races). This value will be used when you first sail a new class, so there is no information for your skill in that particular class.
What if I have not got 10 completed handicap races before the start of the next series?
The records have been processed back to the 25th May 2014 – the start of the Spring 2014 series. If you have not sailed and completed 10 races since 25th May 2014, then your personal handicap for a series will be based on however many races you have completed, ignoring the worst of these results.
What if I have not completed any handicap races before the start of the next series?
You will be considered to have a personal handicap of 0, i.e. sail to the class Portsmouth Number.
What happens to the races when I am OOD/AOOD?
The personal handicap series results will give the standard credit for an OOD duty – the average placing of the best completed races for the minimum number of races needed to qualify for the series, after allowing for the number of OOD races, i.e. OOD on 3 races in an 18 race series (which requires 10 results to qualify) means the OOD points are the average of the best 7 completed race results. The OOD points for the personal handicap series results will be based on the personal handicap derived positions, and not the main class based positions. There will thus be two different OOD points – one for the series results using class Portsmouth Numbers, and another for the personal handicap series results.
What happens to my Personal Handicap when the Portsmouth Number of the class is updated by the RYA?
Your personal handicap is combined with the class PN to give your total personal handicap number. That does not change just because the RYA has decided the class PN should be adjusted. So if the RYA increase the class PN, then your personal handicap adjustment is reduced by the same amount to keep the total unchanged.
How is the Personal Handicap calculated within a given race?
For each race sailed as a handicap race a term known as the Standard Corrected Time (SCT) is worked out. Various algorithms could be used to calculate the Standard Corrected Time. One of the recognised algorithms is that the SCT = average of Portsmouth Number (PN) corrected times of top 2/3rd finishers. If number of finishers to count is a fraction, the number of finishers to be included is rounded up to next whole number.
For each helm that finishes the race the Percentage change PI to the standard boat class PN is calculated such that the resulting corrected time will equal the Standard Corrected Time. Thus:
PI = [ (helm time corrected for class PN) / (Standard Corrected Time) – 1 ]*100 percent
The PI is also expressed as the equivalent increment (PH) to the class PN, rounded to a whole number:
PH = PI / 100 * (class PN)
The values of PH in each race are shown on the race results, and saved in a database to be used to calculate the fixed average personal handicap used for the personal handicap based series results
Is this method of calculating and using Personal Handicap common across other Sailing Clubs?
There is no RYA recommended method, or single method in use by clubs that have at least some form of personal handicap. Further the different ‘standard’ programs used by other clubs, e.g. Sailwave, have different options for personal handicap calculations.
So at present we are using a system based on past recommendations from the RYA plus a bit of common sense for what should work at NHEBSC. At present the algorithms for calculating which finishers are to be used to calculate SCT, and the averaging of PH data over a number of races, should be considered representative but subject to change, in part in response to any feedback provided by club members.
14 February 2015