Robin Hood gives to Mulgan

In this week's readings, I found that Brest, Harvey, and Low (Calculated Impact) had something important to say to Mulgan (Measuring Social Value).

As I read through Mulgan, I appreciated his proposal for a more subjective measure of social impact vis a vis effective demand and effective supply. Trying to assess social impact as an objective standard is a nutty concept, as social values can be observed but not measured (certainly not comparatively).

However, Mulgan's solution--a framework of judgments on a 1-5 scale--seemed a little TOO subjective to me. Shouldn't there be some comparison involved, rather than simply checking later down the line to see if a proposal meets its own standards?

For me, Brest, Harvey, and Low's recommendation to compare the proposal to a real or hypothetical alternative solution solves this problem. I think this should be added to Mulgan's method in the form of a comprehensive competitive analysis.

Is this missing Mulgan's point, or lending his tool some much-needed credibility? What do you think?