BPMN/DMN Decision/Action
- John Svirbely
Description
In a medical business process model, decision logic is often used to direct process flow as "intent" and "recommendation" are executed by means of orders and, eventually, interventions. Process flow is often managed through (exclusive) gateways in a BPMN workflow diagram. This pattern mandates the separation between the "cognitive" aspects – modeled as Decisions that are embedded in a business process – and the proper "workflow" aspects, captured by the business process model.
Problem
The purpose of the (portion of the) pulmonary embolism guideline is to determine the best diagnostic option. As soon as this determination is made, and committed to, the analysis of the input data used in the RGS scoring algorithm can be considered complete. The next step is to execute, based on the outcome of that decision, so that a diagnosis can be reached. If the decision is to order the D-Dimer (justified by a RGS less than 11), then the workflow proceeds in one direction; if the decision is to order an imaging study (supported by a RGS greater than or equal to 11), then the workflow proceeds to a sub-process during which an imaging examination will be ordered.
Applicability
· Complex branching logic in a workflow gateway
· Logic can be incapsulated in a Decision
Pattern
The pattern uses a combination of BPMN – to capture the workflow and the temporal dependencies between the tasks – and DMN to model the actual decision logic. The logic is completely embedded in the decision tasks, and the gateways use simple patterns to express the branching logic based on the decision outcome. Figure 1 depicts the generic form of this pattern as a workflow fragment.
Figure 1 – BPMN diagram with exclusive gateway
The Figure 1 above (BPMN diagram with exclusive gateway) illustrates a generic Business Process Modeling Notation diagram demonstrating the testing of a decision and an exclusive gateway to determine further process flow. The sub-process leading to the gateway must contain the decision logic necessary to determine process flow at this gateway.
Specific Example
The Figure 2 below (pulmonary embolism workup decision) illustrates the process flow for the pulmonary embolism workup decision. A sub-process first collects and displays for review the data necessary to calculate the RGS. Then the process flow enters a decision model (see Figure 42, above, Interpretation of Score Decision Table). Emerging from the sub-process, the decision has been made, and the answer is used to determine which orders should be placed next. The actual modelling of the orders – and the subsequent interventions – varies and is covered by other patterns. In this example, ordering the D-Dimer is modelled as a simple task. Missing is the further workflow and decision-making necessary to choose which imaging modality to order in the alternative scenario.
Figure 2 – Pulmonary Embolism Workup Decision
The Figure 2 above (pulmonary embolism workup decision) shows a sub-process that collects and processes the data necessary for the RGS Decision. Subsequently, this decision is used to choose between two process flows.
Metadata
<blank>
Discussion
<blank>
Related Patterns
<blank>
