Distinction between different scenarios of group decision-making

A few years ago, I was at a mini-conference on information aggregation in decision making, at which there was a lot of discussion of group decision-making procedures, and individual strategies in group decision contexts. I was bothered that there was a lot of talk about decision-making rules, but not so much about the ways that rules interact with the types of decision problems, which I categorized as:

1. combining information (as in perception and estimation tasks)

2. combining attitudes (as in national elections)

3. combining interests (as in competitive games and distributive politics)

I considered three different group-decision scenarios: (1) “inference,” (2) “difference of opinion,” and (3) “conflict of interest,” and discussed demarcation points to identify the scenarios. My claim is that different information-combining strategies are appropriate in these different scenarios, and that blurring these distinctions (for example, thinking of the “marketplace of ideas” or analogizing from Arrow’s theorem of preferences to rules for ranking Google pages) can mislead.

For more, see pages 16-26 of this set of slides.