The way I see it a points system should make a pass worthwhile, no matter which position you are running in. Therefore I calculated the cut off success rate for overtakes for some different points systems.
The way I calculated that value was to calculate the expected gains, for variable percentage of success and rearranged a function for the required percentage of succesful attempts.
rearranged to
with e=0, where g are the gains and l are the losses for a succesful or unsuccesful pass.
I was calculating these values for a situation where a pass might result in an accident and no finish (dashed line) and where the overtaking car might lose 1 position (solid line). I don't include values for passes on direct competition because it results in basically the same curves with an offset, so fundamentally the same curve shapes.
The curve D uses an exponential point distribution, a succesful pass gives you 40% more points in this case and I included 2 old point systems as well.
A lower value for the curves means that you need a lower success rate for overtakes. That means a lower value should lead to riskier overtaking attempts.
A - current system - 25, 18, 15, 12, 10, 8, 6, 5, 4, 3, 2, 1, 0
B - op's proposal - 25, 20, 18, 16, 15, 14, 13, 12, 11, ...
C - linear - 19, 18, 17, 16, 15, 14, 13, 12, 11, ...
D - exp (1.4) - 600, 426, 304, 217, 155, 111, 79, 56, 40, 28, 20, 14, 10, 7, 5, 3, 2, 1
E - "old" system - 9, 6, 4, 3, 2, 1, 0
F - "old" system - 10, 8, 6, 5, 4, 3, 2, 1, 0
Since basically every proposed point system uses a linear scale for the lower positions you end up with the same cut off percentage for the backmarkers when you might lose 1 position.
I find it quite interesting that the old system is quite risk friendly with quite low required succes rates for overtaking attempts.
And while the exponential system might make for an ugly or difficult to remember point system, it seems to be pretty much position independent. So it would make sense to fight for positions no matter where you are running.
D yields constant values because everything but the factor cancel out. (
for accidents and
for 1 position lost, f=1.4 for these values)