BayesiaLab associates a cost with each node. This cost represents the price (in a scale shared by all the nodes) associated with the observation of the value of the node. It makes possible to carry out an adaptive questionnaire that sorts the questions in an optimal order with respect to the pertinence of the questions with the current knowledge state (pertinence expressed in terms of information gain and as- sociated cost).
A node can also be declared as not observable. In this case, it will never appear in the adaptive questionnaire; however, its value can be set manually by using its monitor. A not observable will not be observed either during the interactive inference and the Bayesian updating, nor during batch labeling or batch inference even if this node has a corresponding value in the associated database.
The cost table can be edited by using the contextual menu associated with the graph or through the assistant of the adaptive questionnaire that is available in the Inference Menu Item. This table associates a cost with each variable (1.0 is the default value). A cost must be superior or equal to 1. In order to indicate that a variable is not observable, one has to delete the associated cost (or indicate a value inferior to 1).
The table is sortable by clicking on the header of each column.
The costs can be edited individually for each node by using the contextual menu of the node, or by using the thumbnail Properties of the node editor.
The Import button allows importing a list of costs from a dictionary as in Import Dictionary menu.
The Export button allows exporting the list of costs in a dictionary as in Export Dictionary menu.