Likelihood Ratios
The likelihood ratio of a feature tells you how often it occurs in a document of interest versus how often it occurs in a document that is not of interest. This ratio is shown for several different types of features within the IPS interface.

LR+
In IPS, the LR+ of a term or concept is the likelihood ratio of it being present in a document. In this case, LR+ is the ratio of the term or concept being present in documents of interest versus its presence in documents that are not of interst.

LR-
The LR- is just the opposite. It is the ratio of a term not occuring in documents of interest versus its absence in documents not of interest. Note that LR- is not the reciprical of LR+.

Example: Consider the concept, "fever" or "febrile" or "temperature elevation." The LR+ of 2.203 means that the concept is more than twice as likely to appear in a document of interest than in a document not of interest. The LR- of 0.482 implies that the concept is absent from a document of interest about half as often as from one not of interest.