Interoperability is a key goal of the caBIG® initiative, and reflects the ability of information systems to both access and appropriately use data from a remote data resource. The term "caBIG®-compatible" is used to refer to tools that use shared standards to facilitate interoperability on the caBIG program. Most tools available for adoption from caBIG® are already compatible. Adapting a tool to be caBIG®-compatible is done to achieve interoperability. There are two equally important requirements for achieving compatibility:
- Semantic Interoperability: Systems must "understand" the data exchanged. This "understanding" requires shared data models which, in turn, depend on standard (controlled) vocabularies and Common Data Elements (CDEs).
- Syntactic Interoperability: Systems must be able to exchange data through shared interfaces.
The caBIG® Compatibility Guidelines outline different levels of compatibility, and explain the criteria for achieving these levels.
Four Factors That Determine Compatibility
- Information/Data Models: Developed to represent the interfaces of a system. Also called data models, they describe the relationships between the common data elements in a domain.
- Controlled Vocabularies: An agreed-upon set of standard terminology. Controlled vocabularies are needed to provide shared meaning to data across systems. If we both use the same controlled vocabulary, the terms in my system will match those in yours.
- Common Data Elements (CDE): Use shared vocabularies and standard values and formats to define how data are to be collected. Controlled vocabularies provided a shared meaning, whereas CDEs provide a structure to that shared meaning. CDEs are described in a centralized electronic resource called the Cancer Data Standards Repository (caDSR) and can be searched via the CDE Browser.
- Programming and Messaging Interfaces: Computer programs access resources from other programs through programming and messaging interfaces, also called Application Programming Interfaces (API). Agreement upon standards for these interfaces is necessary for interoperability.
Five Steps to Develop a Compatible Tool
- Creating an Information Model
- Performing Semantic Integration (Vocabularies)
- Transforming the Information Model into Metadata (Common Data Elements)
- Generating Code and Messaging Interfaces (API’s)
- Generating a caGrid Interface
Six key variables will impact the effort and time required to make a tool caBIG®-compatible. Again, these apply if you are taking the adapt path to achieving compatibility:
- Existing familiarity with tools: Access to a development team that has knowledge and skills related to UML and CDE models and tools, Enterprise Architect, and NCI tools such as the Semantic Integration Workbench (SIW), caAdapter, and Introduce will help speed development.
- UML modeling skills: Team understanding and facility with classes, attributes and data types; cardinality; UML structures; understanding of inheritances and associations; and camel case naming conventions will speed development time.
- Projected number of classes and attributes: The projected number of classes/attributes for the tool in question will impact development time.
- Technology/Infrastructure: The following technical environment and infrastructure needs to be in place: Windows, Java WebStart, Internet Explorer 6.0, and the Enterprise Architect software tool.
- Access to Domain Expertise: Access to the appropriate domain specialists to support the data modeling effort will facilitate and speed development.
- Time Availability: Having the team development available to spend concentrated time on the project will help speed efforts.
caBIG Adapt Path: Resources and Support: Resources and tools that can help implement the adapt path
Adaptation Roadmap: Review a number of design patterns that can help plan for the adapt path
Adapt Path Use Cases: See how others have implemented the adapt path.
NCI Semantic Infrastructure and caBIG Compatibility: How the Pieces Fit: Overview of how NCI tools support the compatibility process.
Essentials of caBIG Compatibility: Introduction: Introduces the caBIG compatibility criteria, outlines success criteria for making a tool caBIG compatible, and points to additional resources.
Essentials of caBIG Compatibility: From Theory to Practice – Semantic Annotation: Advanced look at caBIG compatibility, focusing on the practical issues associated with semantic annotation.
Essentials of caBIG Compatibility: From Theory to Practice – Metadata Reuse: Advanced look at caBIG® compatibility, focusing on the practical issues associated with the reuse of metadata.