http://fas.org/spp/starwars/ota/
Actually, I can't, for all the links are dead.
So I don't know how they scored success. I score it:
Integral to winning the Cold War, which we did.
Deterring a first strike, because the Soviets couldn't choose which of their warheads would get intercepted. This is very important because the triad made a successful first strike, that is, one with minimum retaliation, extraordinarily difficult in the first place.
Preventing maximal damage to cities and infrastructure while civilians huddle in their shelters (which we could have built, and stocked with a years worth of food, for 1/3 of the annual DoD budget of the period).
Failing our building shelters, preventing all civilians in their cities and such from getting nuked. That one is iffy, especially since:
At the other end, you could define it as none of the 40,000 warheads in their inventory hitting us, but I know that's not what the proponents of SDI claimed it was capable of.
Note, I was something of a player in this arena during the period in question, including editing the Arpanet ARMS-D mailing list in the 1982-3 period, debating it with the best anti-s MIT had, you're not going to convince me by a raw appeal to authority, especially as filtered through such a notorious organization as the OTA.