This whole question of branding in search came about because of a rather fuzzy definition: what exactly is brand lift? How do you measure it?
This was the problem we wrestled with when we did the first search brand lift study for Google and Honda. Failing anything better, we did the standard tests of aided and unaided message and brand recall. I’m not a huge fan of these metrics, because I don’t think they adequately capture the neural basis of brand. But given the nature of the study (which included a survey and some eye tracking) it was our only feasible alternative.