11 DMN Example
In this section we present an example of the use of DMN to model the decision-making in a
simple business process modeled in BPMN, including decisions to be automated in decision
services called from the business process management system.
11.1 The business process model
Figure 1 shows a simple process for loan originations, modeled in BPMN 2.0. The process
handles an application for a loan, obtaining data from a credit bureau only if required for the
case, and automatically deciding whether the application should be accepted, declined, or
referred for human review. If referred, documents are collected from the applicant and a
credit officer adjudicates the case. It consists of the following components:

The Collect application data task collects data describing the Requested product and
the Applicant (e.g. through an on-line application form).

The Decide bureau Strategy task calls a decision service, passing Requested product
and Applicant data. The service returns two decisions: Strategy and Bureau call type.

A gateway uses the value of Strategy to route the case to Decline application, Collect
bureau data or Decide routing.

The Collect bureau data task collects data from a credit bureau according to the
Bureau call type decision, then the case is passed to Decide routing.

The Decide routing task calls a decision service, passing Requested product,
Applicant data and Bureau data (if the Collect bureau data task was not performed,
the Bureau data are set to null). The service returns a single decision: Routing.

A gateway uses the value of Routing to route the case to Accept application, Review
application or Decline application.

The Collect documents task requests and uploads documents from the applicant in
support of their application

The Review application task allows a credit officer to review the case and decide
whether it should be accepted or declined.

A gateway uses the credit officer’s Adjudication to route the case to Accept
application or Decline application.

The Accept application task informs the applicant that their application is accepted
and initiates the product.

The Decline application task informs the applicant that their application is declined.
Note that in this example two decision points (automated as calls to decision services) are
represented in BPMN 2.0 as business rule tasks; the third decision point (which is human
decision-making) is represented as a user task.
Figure 1: Example business process
11.2 The decision requirements level
Figure 2 shows a DRD of all the decision-making in this business process. There are four
sources of input data for the decision-making (Requested product, Applicant data, Bureau
data and Supporting documents), and four decisions whose results are used in the business
process (Strategy, Bureau call type, Routing and Adjudication). Between the two are
intermediate decisions: evaluations of risk, affordability and eligibility. Notable features of
this DRD include:

It covers both automated and human decision-making

Some decisions (e.g. Pre-bureau risk category) and input data (e.g. Applicant data) are
required by multiple decisions, i.e. the information requirements network is not a tree

Business knowledge models (see Affordability calculation) may be invoked by
multiple decisions

Business knowledge models (see Credit contingency factor) may be invoked by other
business knowledge models

Some decisions do not have associated business knowledge models

Knowledge sources may provide authority for multiple decisions and/or business
knowledge models.
Figure 2: DRD of all automated decision-making
It might be considered more convenient to draw separate (but overlapping) DRDs for the
three decision points:


Figure 3 shows the DRD of the decisions required for the Decide bureau strategy
decision point, i.e. the requirements subgraph of the Strategy and Bureau call type
decisions. These are decisions to be automated through encapsulation in a decision
service called at this point, and therefore need their logic to be specified completely.
Figure 4 shows the DRD for the Decide routing decision point, i.e. the requirements
subgraph of the Routing decision. These are also decisions automated with a decision
service, and therefore need their logic to be specified completely. Note that some
elements appear in both Figure 3 and Figure 4.

Figure 5 shows the DRD for the Review application decision point, i.e. the
requirements subgraph of the Adjudication decision. This is a human decision and
has no associated specification of decision logic, but the DRD indicates that the Credit
officer takes into account the results of the automated Routing decision along with the
case data, including the Supporting documents. (The requirements subgraph of the
Routing decision has been hidden in this DRD.)
All four DRDs – Figure 2, Figure 3, Figure 4 and Figure 5 – are views of the same DRG.
Figure 3: DRD for Decide bureau strategy decision point
Figure 4: DRD for Decide routing decision point
Figure 5: DRD for Review application decision point
The DRG depicted in these DRDs shows dependencies between the following decisions:

The Strategy decision, requiring the Bureau call type and Pre-bureau eligibility
decisions, invokes the Strategy table shown in Error! Reference source not found.
(without that table being encapsulated in a business knowledge model)

The Bureau call type decision, requiring the Pre-bureau risk category decision,
invokes the Bureau call type table shown in Error! Reference source not found.

The Eligibility decision, requiring Applicant data and the Pre-bureau risk category
and Pre-bureau affordability decisions, invokes the Eligibility rules shown in Error!
Reference source not found.

The Pre-bureau affordability decision, requiring Applicant data and the Pre-bureau
risk category and Required monthly installment decisions, invokes the Affordability
calculation boxed expression shown in Error! Reference source not found., which
in turn invokes the Credit contingency factor table shown in Error! Reference
source not found.

The Pre-bureau risk category decision, requiring Applicant data and the Application
risk score decision, invokes the Pre-bureau risk category table shown in Error!
Reference source not found.

The Application risk score decision, requiring Applicant data, invokes the score
model shown in Error! Reference source not found.

The Routing decision, requiring Bureau data and the Post-bureau affordability and
Post-bureau risk category decisions, invokes the Routing rules shown in Error!
Reference source not found.

The Post-bureau affordability decision, requiring Applicant data and the Postbureau risk score and Required monthly installment decisions, invokes the
Affordability calculation boxed expression shown in Error! Reference source not
found., which in turn invokes the Credit contingency factor table shown in Error!
Reference source not found.

The Post-bureau risk category decision, requiring Applicant and Bureau data and
the Application risk score decision, invokes the Post-bureau risk category table shown
in Error! Reference source not found..

The Required monthly installment decision, requiring Requested product data,
invokes the Installment calculation boxed expression shown in Error! Reference
source not found..

The Adjudication decision requiring Applicant data, Bureau data, Supporting
documents, and the Routing decision, has no associated decision logic.