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How to Adjust?

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Oli View Drop Down
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Post Options Post Options   Quote Oli Quote  Post ReplyReply Direct Link To This Post Topic: How to Adjust?
    Posted: 24 Oct 14 at 5:20pm
So we've had some debate recently on PY with the usual plethora of trolling and banter, but no real benefit to anyone out there looking for a solution.

So genuinely i would like to know who on here adjusts and their method of doing so.  If you feel the need to make a comment on how One design is the best and that handicap racing is just for fun then please take it as we already know.  Just the facts on the methods employed by the clubs that do adjust, or if we lived in a world were we only had the choice of using the PYS site how would you adjust?

Do you use a percentage system, use Gl data, or something else?

It would be interesting to see others methodology and perhaps a few of the usual "non-believers" could use some brain matter to working with what is out there for a solution. 

lets see how many actually try and come up with something rather than just saying "nope doesn't work, its crap, cant be bothered".

(i'd just rather see a proactive approach than just the same old moaning that goes on here)
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JimC View Drop Down
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 14 at 5:33pm
We used to use the RYA spreadsheet. Most recently we looked at the PYS site, but the current published numbers are within a point or two of what it comes up with for us, so we decided we may as well use the published numbers for this year. For unpublished boats I usually make a suggestion to the Sailing Sec based on last published number, similar for old development boats. For new boats we look and see if anyone else has a guess and also do a "well, probably faster than an x and slower than a Y. That should do for now" paper exercise.
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marke View Drop Down
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Post Options Post Options   Quote marke Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 14 at 5:53pm
We have been adjusting at Starcross for about 5 years now - largely as a result of the RYA scheme not keeping up with the development classes back in 2009.  All of our racing is on open water with average lap handicap scoring, but we have a number of class fleets within each of the handicap racing.  Typical turnout is 30-50 boats

We have an annual PN review and do the analysis on our database of recorded elapsed times that our race management software archives automatically.  We have our own PY analysis software which allows us apply the RYA (and Great Lakes) algorithm to different samples from the database (e.g time periods, classes, types of races etc.).  The software also churns out distributions of performance by class (quintiles and deciles).

We focus the analysis on our main racing classes (Merlins, RS200, RS400, Laser, Radial, Hornets) by comparing relative performance at the upper quintiles - this seems to be a pretty good approach and we have very close racing between these fleets (subject to factors such as wind strength, courses, tide - which tend to average out over a series)

Once we do the analysis the data goes to the fleet captains to decide whether to apply adjustments.  The overall policy is not to make a change unless the data is convincing.  We also monitor some metrics about how the classes are distributed in our series and trophy races - and I always re-score last years races with the proposed changes so we can see what the impact would be (As JimC reports the changes are usually very small unless you make very significant changes to the PN).  Since we started making the changes there has been a noticeable increase in the number of different classes appearing top ten.

Some issues:
 - we think the SCHRS system works better for multihulls than the RYA system
 - establishing a PN for a singleton class is hard - but if it is a club member who has sailed other classes at the club to establish their skill level we can have a stab at it where an adjustment appears to be required.  We are very wary of making this type of change without strong evidence.

For the last couple of years the local PNs have been stable and the RYA and Great Lakes numbers have moved to be pretty much in line with our numbers - the one exception being the Laser and Radial where we are close to the Great Lakes numbers but a fair distance away from RYA.  Open water sailing against largely faster classes I think.

We only changed two classes this year - Icon down to 969 from 978, and Wayfarer back to its RYA number.

I think the real benefit for us as a club has been that while new boats with the wrong initial PY will appear, or old boats will get a performance-enhancing makeover now and again, we have our own process by which inequities will be resolved.

Mark


Edited by marke - 24 Oct 14 at 6:18pm
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AlexM View Drop Down
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Post Options Post Options   Quote AlexM Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 14 at 5:54pm
We use the PYS website at Leigh and Lowton.
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%

We also apply 1.5% max/min adjustment from the RYA PY number so we don't penalize the really good/bad classes. In our case the Ents & 300 and at the other end the Toppers.
Current data below:
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Post Options Post Options   Quote sargesail Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 14 at 11:12pm
Wow - even given the percentages applied to the suggested PN I'd definitely bring the 2000 not the 300 to L&L.  (If I actually cared about handicap results....)
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Post Options Post Options   Quote craiggo Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 14 at 11:56pm
We use PYS, but don't have enough data to get a high confidence factor on anything, so understandably there is some reluctance to move anything. Some of the suggested PYs on PYS are so extreme that it would be crazy to adjust all the way, but they are largely driven by single boats or two boats.

For boats without official numbers I normally come to an agreement with the owner and it's adjusted where necessary to on average out then where they expect to be in the fleet.

For Cruisers we use Byron numbers and don't adjust. This is because several of our members didn't want the numbers to be adjusted to make it easier for them, and wanted to genuinely know when or if they were improving. I have dual scored with NHC, but the system has massive failings and our members and I still do not buy in to it, so we'll stay with Byron for now.
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Oli View Drop Down
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Post Options Post Options   Quote Oli Quote  Post ReplyReply Direct Link To This Post Posted: 25 Oct 14 at 3:35pm
Marke, sounds like you guys do a fair bit of analysis at starcross, you say you have a few handicap fleets, do you have any all in races?  how would you / do you compensate for the wider spread in handicaps?

the question that gets raised with us is that we have 2 handicap fleets and the slower fleet says they cant compete with the faster fleet in our all in races. We added more all in races to increase the data, but the numbers may still be biased towards one fleet or the other.  This is where variables in wind and tide on the day can disprove most theories.

Alex M, how do you determine a handicap on a percentage system for a boat that has no national number to base it off?  i suppose if the adjustment is 100% until it reaches 0.3cf that could acts as harsh best guess like others clubs use.  What if the initial number is more favorable?

Craiggo, do you ever race cruisers and dinghies?

All, how often do you adjust?  It seems most apply a conservative approach to the amount you move a boats handicap so do you only adjust once or twice a season?  sailors are stuck with a number all year but its not too far removed from their base.  If you adjust more harshly would you adjust more often?  Giving a chance if the number is wrong to move quickly so the sailors don't feel penalized.

Thanks for you replies so far, all very interesting.




Edited by Oli - 25 Oct 14 at 3:44pm
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marke View Drop Down
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Post Options Post Options   Quote marke Quote  Post ReplyReply Direct Link To This Post Posted: 25 Oct 14 at 6:35pm
Oli

We do have about ~15 "all in" races during the year, and we include these in the analysis.  We use average lap timing - and typically the very slowest boats will do one lap less than the fastest.  Are you sailing on tidal waters - that may explain the differences between the two fleets.  We sail on tidal waters, but it is an estuary and competitive boats tend to find ways to avoid the tide.

We review once per year - but in the first year of adjustments we had a six month review as the changes were quite significant at the time.

Mark


Edited by marke - 25 Oct 14 at 6:35pm
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craiggo View Drop Down
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Post Options Post Options   Quote craiggo Quote  Post ReplyReply Direct Link To This Post Posted: 25 Oct 14 at 8:48pm
We have about 6 races a year that are all in, including Cruisers. We use the Byron numbers for the cruisers and the PY numbers for the dinghies. As Byron numbers are referenced to some of the better determined PYs of old we dont find too much trouble in using them in an all in race.
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Post Options Post Options   Quote transient Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 14 at 7:06pm
Quick question to you result gurus:

How much time do you spend each week submitting returns and sorting out local adjustment?
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