The optimal aggregation of (expert) opinion has been a focus of much research, and there is a clear resemblance to the problem of the optimal combination of multiple items or tests (e.g. Meehl, 1999). For binary choice situations with a correct alternative, it has been shown that a weighted sum of individual choices is the optimal aggregation rule, where the weights proportional to the odds of ...

Ongoing research in the Rockefeller College of Public Affairs and Policy is focusing on strategies for efficient and effective model building in groups. The intent is to involve a relatively large client group in the business of model formulation, not just conceptualization. Recent projects have explored strategies for accelerated group model building in the context of three public policy probl...

This paper presents a group-theoretical vector space model (VSM) that extends the VSM with a group action on a vector space of the VSM. We use group and its representation theory to represent a dynamic transformation of information objects, in which each information object is represented by a vector in a vector space of the VSM. Several groups and their matrix representations are employed for r...

People in densely populated environments typically form groups that split and merge. In this paper we track groups of people so as to reflect this formation process and gain efficiency in situations where maintaining the state of individual people would be intractable. We pose the group tracking problem as a recursive multi-hypothesis model selection problem in which we hypothesize over both, t...