Entering and Retracting Findings

Purpose:  Usually you enter findings (sometimes called “evidence”) to temporarily apply a Bayes net to a particular case for probabilistic inference.

Entering/Right-click:  To enter a finding for a node, right-click on it and choose Enter Finding.  Each possible state of the node will be listed in alphabetical order; choose the finding from it.  Menu items appear as state title (or by state name if no titles exist).  

 After the finding has been entered the node will be darkened (or its color otherwise changed as defined by node-sets).  It does not matter in what order you enter a set of findings.

Entering/Left-click:  When the net is compiled and the node is displayed in belief-bar or meter style, left-click directly on the name of the finding you wish to enter.   If the node is displayed in belief-bar style then a solid outlined bar is drawn for the state matching the finding.

When you enter new findings, and belief updating is not yet done, only those nodes effected will have their beliefs indicated invalid.

Retracting:  If you wish to retract (i.e. remove) a finding that you have entered for some node, choose Unknown from its findings menu, or click again directly on the name of the finding of a belief-bar node.  Entering a finding and retracting it is equivalent to never having entered it, even if there were other findings entered in between.

Another way of retracting the findings for some nodes is to select them and then choose Cases Remove Findings, or click the toolbar button with a red cross over the case symbol: image\DelCaseTOOL.gif

If you wish to retract all the findings entered for all the nodes in the net, make sure all or none of them are selected, and then choose Cases Remove Findings.  This is useful if you are finished with one case and wish to move on to another.

Multiple Nodes:  You can enter the same finding for a whole set of nodes at once.  First select them, then right-click on one of the selected nodes, and proceed as above.  More Info  

Uncertain:  If you want to enter a finding that a node is not in a particular state, or you want to enter an uncertain finding, you would enter it as a negative or likelihood finding.

Consistency:  Netica can check the consistency of the findings you enter.

Sets of Findings:  If you have multiple findings to repeatedly enter into a Bayes net, you can put them in a case file.

Decision Nodes:  Entering a finding into a decision node does not really correspond to discovering information or making an observation, but rather to committing to a decision choice.  Nevertheless, it is still often loosely referred to as "entering a finding".