Michael:
Mike Shannon, who used to be the Head Professional at Isleworth (I recently heard he now teaches at Sea Island), is heralded as a very good putting instructor (he's worked with a lot of guys on tour). He was the first person I heard that used this tool for statistical analysis. For tracking purposes, he added the feet of putts you made, with 1' being the minimum and 10' being the maximum (if you made a 50 footer, it still counted as 10', a putt from 3" counted as 1'. This keeps your tracking from getting skewed by making a bomb). His benchmark was 50' for a reasonable putting round, if I recall correctly. I think this helped take into account rounds, for example, if you hit 18 greens 40 feet from the hole each time and had 50', you averaged 2.78' on the putts you holed which would be an adequate result in that case. When you start factoring in missed greens, that is when you see how you are really performing. If you hit 7 greens and only made 40 feet of putts, you need some serious help.
I found this tool to be very effective because it helps identify if you are making the putts that help you score. I'm sure there may be some deficiencies in the exercise, but overall, if the average number of feet you make in a round increases over time, you are doing something right. I remember one of Mike's examples of a good putting round was somewhere around 120' (remember, 10' is the highest numner you can use) by Sonny Skinner in the Buick Open. Of course, it helped him shoot 62.
I hope this puts it in perspective. Try it and see what it tells you! I think if you find yourself making 60'-70', you'll be posting pretty good scores.
Regards,
Doug