Tallis Composer User Interface: Decision Candidates
Decisions: Creating a decision based on results of an enquiry
Decisions are tasks in which a choice is made between several different options, known as candidates. PROforma supports decision-making through a mechanism for generating arguments that may be either for or against a given candidate.
Candidates Tab
To create a new candidate, enter the following information:
| Name | An alphanumeric string representing the candidate’s ID (e.g.: ReferToGeneticist) |
| Description | A text string displayed to the end-user as one of the decision options when the decision is enacted (e.g.: The patient is eligible for referral to a geneticist) |
| Priority | An integer value representing the a-priori importance of the candidate (if several candidates have the same netsupport, candidate priority is used to determine the order in which they are displayed to the end user). |
When all the data is entered, click Add.
The new candidate will be added to the Candidate list.
Next, you have to add arguments for (or against) the candidate. To do this, select the Arguments tab.
Arguments Tab
The top drop-down box contains a list of the decision’s candidates. Select the candidate for which you want to define arguments, and enter the following information:
| Description | A text string displayed to the end-user during enactment (to represent the argument). If there is no description, the condition is displayed instead (e.g.: Blood pressure is lower than 120). |
| Condition | A truth-valued expression that represents the circumstances under which the argument applies (e.g.: blood_pressure < 120) |
| Support | The support that the argument offers if the condition is true. The four categories of symbolic support are:
|
When all the data is entered, click Add.
The new argument will be added to the Arguments list.
When a decision is enacted, the condition and the support properties are used by the engine to determine the effect of each argument and in turn the value of the net support for a given candidate. A recommendation rule is then used to determine whether or not a particular candidate is recommended.
To define the recommendation rule for the candidate, select the Decide tab.
Decide Tab
Select the candidate for which you want to define a recommendation rule from the drop-down box. The Rule field is pre-populated with a default decision rule expression: netsupport(CurrentDecision, CurrentCandidate) >= 1
The default rule states that for the candidate to be recommended, its aggregated support (or “netsupport”) has to be greater than or equal to 1. The recommendation rule can hold any truth-valued expression.
Note: Selecting Unlocked in the Rule Input Mode field resets the recommendation to the default rule.