An interesting question came up last night in my Dresden Files campaign. The practitioner was conducting (casting) electricity from himself to a hapless white court vampire to fry the poor chap. He put 7 shifts of power into the spell, and rolled a 3 on his discipline roll. He tagged his aspect of
Struggle for Power for a +2 bringing his final roll to 5. At this point, he didn't want to spend any more fate, so took backlash for 2 stress to get the roll to 7 and successfully cast the spell.
My question is, would his targeting roll be affected by the backlash or not? I know that he loses none of the power of the spell since he took backlash, but I'm just not sure if that makes up for the targeting also. The book explicitly states in the example of fallout on
YW251 that in that case the power and targeting are reduced. But it only states in the example of Backlash on the same page that power is not reduced, and doesn't mention targeting.
Updated to re-add research and further links/information.
I think I found an answer on the DFRPG forum.
A quote from the post is below:
The book says nothing about taking backlash raising your roll or counting as any kind of bonus. It says "Any uncontrolled power taken as backlash remains a part of the spell and does not reduce its effect. Fallout is different: every shift of fallout reduces the effect of the spell."
The power remains a part of the spell, that's all. The attack roll isn't part of the spell's power, any more than the attack roll with a gun is part of the gun's Weapon damage.
This seems to make the most sense to me, though I ruled in the players' favor as I tend to do when there are any questions. But I still don't see an official answer, so I guess I'll have to keep searching.
UPDATE: I went to the source, and this is what Fred Hicks had to say on the subject:
To a comment near the top -- IIRC, mathematically, invoking an aspect for a reroll only makes sense when the roll was at -2 or lower. If your guy had a Great discipline, no extra modifiers on control, and rolled a -1 to get a control of 3, then invoking for the +2 was the right move. :)
The guy -- you, I believe! -- quoting "the attack roll isn't part of the spell's power" is on target. :)