What does the GAP 98 document say?

GAP scoring was developed for FAI by Gerolf Heinrichs, Angelo Crapanzano and Paul Mollison. The idea was to get a fair scoring system that was easily adaptable to any competition everywhere in the world, both for hang gliding and paragliding, with a philosophy easy to understand for the pilot, regardless of the mathematical complexity. To compare different tasks within the competition and to adapt the scoring to hang gliders or paragliders, different flying sites, pilot’s level and task philosophy, before the competition the meet director sets some parameters.

Is GAP easy to understand? We'll see if this is true as we proceed through this series.

One of the major scoring decisions that these three made was to apportion the points available to all pilots depending on whether they got to goal or not, depending on how fast they flew, depending on how early they started and in what order they arrived at goal. This is how they decided at first to apportion the 1000 available points, points that they thought each day should be potentially worth:

These essentially hand drawn curves express the idea that as more pilots make it into goal more points should be available for speed to give more reward to the pilots who went faster and less to distance, as getting to goal apparently wasn't that hard and getting distance was therefore not such a big deal. Arrival position and departure time points are a portion of the speed points (actually a portion of what's left over after the distance points are subtracted from the 1000 points), providing, it was hoped, some small incentive to go as early as possible, offsetting the risk of being out in front, perhaps alone.

Note the speed line at zero percentage of pilots at goal actually goes to zero points, although the graph doesn't show this. Arrival and Departure points also go to zero if no one gets to goal. This leaves us with 900 points for the pilot who goes the furthest on a day no one makes goal, which may or may not be a good thing. Is there a good reason to devalue such a day, other than it looks that way on the chart?

In order to use this pretty picture for actual scoring they came up with equations that matched the curves (that's right, the picture came first, then the scoring equations). I've had Excel chart a picture based on the equation that they came up with:

Now one might quibble that the pilots who landed out shouldn't get any points, but unfortunately that would encourage meet directors to call tasks that would be considered by most pilots to be too short.

Their work wasn't done and as they saw how the scoring system worked they decided to make some changes. Next came a revision to GAP 98 that eventually became GAP 2000:

In this iteration speed was now relatively less important as more pilots made it to goal and the pilots who didn't make it to goal didn't get hurt quite as badly. Also there were slight changes to Departure points with its multiplier increasing from 1.2 to 1.4, upping their value a bit. This is essentially the distribution of points that we've been living with since 2000.