The RANKING LADDER Guide

Updated by Rick Hawkeswood, Jan 2006

INTRODUCTION

The idea behind the pilot ranking system is to bring scoring from the league and the nationals into what the HG Competition Committee sees as the correct balance.

This is achieved by using a ranking ladder which is designed with the following ideals:

· The 'Weight' of each round depends on the number of pilots and the task validity:

Each comp day has a 'weighting' in its effect on the pilots ladder score, i.e. the ladder is a ‘weighted average’. So a high validity task with a lot of competitors will have a lot more effect on the ladder than a few pilots on a poor task.

However even low-validity tasks are still scored out of 1000 pts, so they won't pull your average down, instead their effect on the average is decreased. Note that use of GAP scoring means that short tasks will get a low validity, as GAP has minimum-task-length and minimum-task-duration parameters.

· Bias towards the Nationals:

The nationals are given a higher weighting because this is the one time during the competition season where pilots from throughout the country fly together with the same tasks, sites and conditions. The larger numbers of pilots there will automatically give a higher day-weight, but we use a 'Nationals bias' to increase this further.

· Fast Rise:

A hot-shot pilot, newly returned from overseas, should be able to leap up to where they belong on the ladder within a seasons flying. So the weightings have been chosen such that attendance at the Nationals and several weekend comps will give a total weighting of around 100%.

· Slow Fall:

HG skills aren't lost overnight. A good pilot who misses a season should still be ranked as a ‘reasonable’ pilot. So just as a gliders sink rate is about 200 fpm, your ladder sink rate is 200 points-per-year. Between seasons this amount is subtracted from each pilots score.

· Fly as many comps as you want:

There is no limit, but there's no unfair advantage either, as you'll just be stabilising out at your 'natural' level. However if you don't fly in many comps you'll find it hard to regain the 200 points which is subtracted from you Ladder score between seasons.

So get out there and compete!

PILOT RANKING FORMULAE

The pilot ranking formulae following may seem a little mathematical. The problem is that a fair system is a mathematical process that must be written down in a manner that will stop all ambiguities and arguments.

To aid understanding, after reading the PILOT RANKING FORMULAE, have a look at last years Ladder in spreadsheet form, which should be available on the NZHGPA website.

NUM COMP Number of entered pilots, willing and able to fly a league round, if required (i.e.

the number that went up the hill that day).

NUM_FOR_100% = 200 This is the number of entrants required to give a 1000 point day a ladder weighting of 100% (i.e. 20 pilots would have 10% weight).

SINK_RATE = 200 This amount is subtracted from each pilots ladder score between

seasons, so those who stop flying gradually drop off the ladder.

NATIONALS_BIAS = 1.25 The weighting of each Nationals day is multiplied by this amount. Its value is 1.00 for all other comps.

TASK_VALIDITY value between 0 and 1000, generated by the scoring program.

ROUND_WEIGHT = NATIONAL_BIAS

TOTAL_WEIGHT is calculated for each pilot as the sum of the ROUND_WEIGHTs for all the rounds they entered (note this value may exceed 100%).

LAST_YR_WEIGHT = 100% - TOTAL_WEIGHT. (minimum value = 0%) i.e. this is the percentage of last years ladder which will be used in the final calculation for this pilot.

LAST_YR_LADDER The ranking ladder value of this pilot at the end of the previous flying season.

SCORE_THIS_YR YEAR =

Note how this value is self-limiting if TOTAL_WEIGHT is greater than 100%.

SCORE_THIS_YR+

NEW_LADDER = LAST_YR_WEIGHT (LAST_YR_LADDER-SINK_RATE)

WORLD TEAM SELECTION SCORE

The WTS will be calculated using the Ranking Ladder at the end of the competition series prior to the worlds. Two prior seasons are used, or a suitable period as defined by the Comp Committee once the World’s dates are known.