Bob is correct. GHIN pulls this automatically which is from your as far back as your 9/1/16 revision. But for those services that don’t flat out tell you, you look for the lowest between 9/1 of last year and 8/15 of the current year.

By using 12 month index, I believe you are penalizing the vast majority of honest golfers to catch a few cheats. A person with an index of 18 on 9/1 and a 23 on 8/15 is not the same as a person with a 23 on 9/1 and an 18 on 8/15.I am assuming there is a gradual change in index over that time period. They should not be playing in the same flight !! The committee has ways of dealing with sandbaggers that does not have to affect the majority of honest golfers.

For the last 3 years I have had to play to a lower index than I had at 8/15 and actually felt it was a motivation to me to play “to my potential” instead of backing into winning something with an inflated index. I post all my scores and record a score for every round I play even if the game is based on points. The lowest index for 12 months is FAIR.