When I first spoke of SFR, I suggesting calculating, based on faction-size estimates, how many points would make B beat C if the faction is bigger than the A faction, but not otherwise.
I posted some formulas for that purpose, given various different kinds of assumptions about that faction-size information. Lately I've been speaking of SFR as more of a subjective intuitive giving of a small boost to B, an amount subjectively perceived as enough to close the gap with C if B has more support than A, without being enough of a boost to unduly risk helping B beat A if A has lots of support. I advocate both approaches. The calculated SFR is based on subjective estimates, making its apparent objectivity illusory. Still, if they're reasonable estimates, or if the B voters know that the A voters are basing SFR on some reasonable set of estimates, then the B voters should thereby be deterred from defecting. Even though the estimates are subjective, the B voters still know that they're probably good estimates, as good as any. But the same can be said if the SFR is based directly and entirely on subjective perception of the amount that will do the job. Some might prefer estimates about faction-size, and a formula. Maybe most wouldn't. As I said before, I suggest subjective SFR is what sincere rating really is. And so there's good deterrence against defection against voters who rate sincerely. Mike Ossipoff ---- Election-Methods mailing list - see http://electorama.com/em for list info
