A feature is a high-level concept that you can define (with rules) to make further rule building easier. For example, you could define the feature “IsDiabetic” which would be given if the clinical notes indicated that the person was diabetic. This feature could then be used as a condition is subsequent rules that add comments to the interpretive report. The feature itself does not appear in the report.

There are several advantages to using features:

  • Conditions using features may be more intelligible than using more complex expressions involving attributes
  • A feature may be defined as a shorthand way of expressing a pair (or more) of conditions that often are used
    together
  • A feature is easy to find and re-use in different rules
  • The same feature may be defined in more than one way, e.g. “IsDiabetic” could also be given if the GTT 2 Hr result was at a certain level
  • Features make the project less dependent on naming conventions, units and even test values used by the Online Information System. For example, if your diabetic-related comments used the feature IsDiabetic, referring to a high GTT 2 Hr result. If the Online  Information System changed the name of the test, you would only have to redefine your feature IsDiabetic, rather than all the diabetes-related rules. Similarly, if the clinical guidelines that define diabetes change, you again need only change your IsDiabetic feature, rather than all the diabetes-related rules.

A feature comprises of a name and a description. These are set when you add a feature to the case using the Rule Wizard (see Selecting a Feature). The description may be modified at any time by right-clicking on the feature or derived feature in the feature or derived features panes and selecting the rename menu or the features menu to show the feature editor.

Any features given for the case are shown in their own window on the main screen, ordered alphabetically. You can see the definition of a feature by placing your mouse  cursor over the feature, or by selecting it and using the right-click menu ‘Show conditions…‘.

Derived features are used in exactly the same way as features. The difference is that derived features can be defined using features. That is, a derived feature can be considered as a higher-level feature. For example, you might have already defined three features XNormal, YNormal and ZNormal. There may be rules where you want to use these 3 features together. Rather than repeating these 3 features in conditions each time, you can then define a derived feature XYZNormal which is given if the
other three are given, thus simplifying these rules.