  Elicitation of probabilities is one of the most laborious tasks in building
decision-theoretic models, and one that has so far received only moderate
attention in decision-theoretic systems. We propose a set of user interface
tools for graphical probabilistic models, focusing on two aspects of
probability elicitation: (1) navigation through conditional probability tables
and (2) interactive graphical assessment of discrete probability distributions.
We propose two new graphical views that aid navigation in very large
conditional probability tables: the CPTree (Conditional Probability Tree) and
the SCPT (shrinkable Conditional Probability Table). Based on what is known
about graphical presentation of quantitative data to humans, we offer several
useful enhancements to probability wheel and bar graph, including different
chart styles and options that can be adapted to user preferences and needs. We
present the results of a simple usability study that proves the value of the
proposed tools.
