Winston,

I've already given you the answer. I've shown you that Impact Values take no account of field size.

Impact Values try to measure the effectiveness of a group with a certain characteristic.

But the process to determine an Impact Value ignores the field sizes of the races that group participated in.

Amazingly you suggested "% of runners" (for that group) somehow took account of field size. It doesn't.

Here is an example intended to demonstrate how Impact Values can draw the wrong conclusion.

Group A has a certain characteristic that Group B lacks.

Assume that an A and a B compete in races with field size 2.
And that 1 A and 9 ** run in races with field size 10.
There are 100 races with each of the field sizes.

Now if both A and B have the same chance of winning, then As should win 60 (=50+10) of the 200 races.

The 4 totals used to calculate the Impact Value are:

60 = A Wins
200 = Total Wins

200 = A runs
1200 = Total runs

The Impact Value is 30% / ~17%

= 1.80


This wrongly suggests that As should win 80% more than their fair share of races.

In fact both A and B have the same chance of winning, it's just As were lucky is running in a disproportionally high number of piddly races.

Winston, you claim to be very knowledgeable about Impact Values yet never once has it dawned on you that they can have a fatal flaw in disregarding field sizes.

Even after I told you about that flaw, you did not bother to check for yourself but instead clung on to your cherished belief of your self-assessment.