Overview

The openEHR Decision Language (DL) and model defines a formalism for expressing decision logic and rules used by process-oriented healthcare information systems, active forms and so on. Decision logic usually sits within a larger environment of plans, guidelines and data sources such as the EHR, as described in the openEHR Process and Planning Overview. The primary encapsulation of DL is within a Decision Logic Module (DLM).

Within the openEHR ecosystem, Task Plans and GDL3 guidelines both require a way of expressing rules and declaring input variables. Guidelines additionally need a way of declaring output variables. These needs are achieved with the flexible use of a single kind of multi-section module called a decision logic module (DLM).

The Decision Language is a high-level language in which modules containing the following elements may be written:

  • reference data: domain constants;

  • input variables: data items representing external variables relating to the subject (i.e. patient);

  • conditions: Boolean-returning domain-specified criteria;

  • rules: domain-specified rules structures based on condition/action structures, which may return any type;

  • rule-sets: related sets of rules in various forms, including decision tables;

  • outputs: computed results of rule invocations, including logic trace information;

All symbolic elements, including constants, variables and rules may be treated as codes for which a translation terminology is supplied, enabling a DLM to be translated and presented in any natural language.

Requirements

The requirements of openEHR Decision Language fall into a number of categories, described below.

TBD: this section only very rough for now.

Caller Interaction

  • the ability to capture the reasoning chain for presentation to a caller as a justification;

  • the ability to provide a decision and its possible outcomes, with the current recommendation indicated;

Representation

Binding to Data Context

  • bindings that connect variables to external data sources;

Type System

  • an ability to use externally defined information models that supply types that may be used in DL statements.

Execution Model

TBD: