At 18:58 31 January 2018, Jim White wrote:
At 02:15 31 January 2018, Michael Opitz wrote:

George Moffat and the sailing crowd have always proposed to
drop
both the individual pilot's best and worst days because "that's
what
they do in sailing". You might be able to do that in a Grand Prix
format where each day counts the same. I don't see how we can
do
that as long as we have devalued days. A pilot can be a day
winner
on a very difficult 600 point day, and be forced to drop his
day win because all of the other contest days weren't devalued,
even though he had another day where he only got 850 points
compared to that other day's winner?

Please tell me how you propose to make that fair?? I can't see it
being done without a total overhaul of the scoring system.

RO

I have never understood why a difficult day gets devalued. Seems
to me tha
difficult days are a better test of skill.

Devaluation also has the effect that CDs try to set 3 hour tasks.
Why i
the window is short?

Not devaluing days would remove some complexity and IMO
improv
competitions!

Jim

I don't know what your devaluation rules are in the UK, but in the
USA, the rules say that the daily task should be set so that the
winner should take at least 3 hours to complete it (as a fair test of
nationals level soaring skills). There are times when the weather
window will not allow the total time needed to launch and fly a
three hour task, but a two hour (or 1.5 hour) task would be "in the
cards" in order to get a valid contest day in the books, and to
possibly preclude a "rained out contest" (due to not having the
required amount of contest days). Instead of counting the
shortened days equally to the full length days, they are devalued
proportionately. Otherwise a 5 minute error could cost a pilot
twice as many points on a 1.5 hour task compared to a 3 hour
task. As the task time decreases, the points per minute goes
up quite quickly unless devaluation kicks in.

Other devaluation rules pertaining to a low percentage of task
finishers due to an over-call or weather related luck factors have
been added as well. If there is a speed task that nobody is able to
finish (in the USA rules), the winner on a day like this would not
be eligible for any speed points - only distance points - and thus
would only be eligible for a maximum of ~600 points (if landing
just short of the actual finish line - arc, point, goal, etc). At one
time there were scoring systems (FAI rules?) for when there were
no finishers, the day would revert to full value based on distance
achieved, as it was seen as a fair distance task at that point. I
don't know if the FAI still has that in place or not.

I am not on the USA rules committee, so I'm sure there are
others that are much more familiar with the reasons why certain
rules were written the way they were. Those people with a
better understanding can add to and correct any errors that I
have made here.

RO