  When making important decisions such as choosing health insurance or a
school, people are often uncertain what levels of attributes will suit their
true preference. After choice, they might realize that their uncertainty
resulted in a mismatch: choosing a sub-optimal alternative, while another
available alternative better matches their needs.
  We study here the overall impact, from a central planner's perspective, of
decisions under such uncertainty. We use the representation of Voronoi
tessellations to locate all individuals and alternatives in an attribute space.
We provide an expression for the probability of correct match, and calculate,
analytically and numerically, the average percentage of matches. We test
dependence on the level of uncertainty and location.
  We find overall considerable mismatch even for low uncertainty - a possible
concern for policy makers. We further explore a commonly used practice -
allocating service representatives to assist individuals' decisions. We show
that within a given budget and uncertainty level, the effective allocation is
for individuals who are close to the boundary between several Voronoi cells,
but are not right on the boundary.
