Here's another example (on SGC's registry) that I've noticed for some time that makes no sense.
The following link is to a complete Butter Cream set, which includes the Ruth (!), and is listed as the second-best set with a "superiority" rating of 40.49:
http://www.sgccardregistry.com/set.a...4&userset=1398
The following set is missing only the Ruth, but because the overall condition is better, is listed No. 1 with a rating of 42.68:
http://www.sgccardregistry.com/set.a...4&userset=5062
I don't get wrapped up in registry rankings, so I find it more funny than anything else that a Butter Cream set missing the Ruth -- one of the truly rare cards in our hobby -- can be judged "superior" to one than has it. I'd say there's a serious flaw in the formulas the companies use.
The Butter Cream rankings:
http://www.sgccardregistry.com/regis...?cat=1&set=374