Why Centralized Data Banks Won’t Work

for Health Information Exchange

Rex E. Gantenbein PhD, Senior Member IEEECenter for Rural Health Research and Education

University of Wyoming

rex@uwyo.eduhttp://www.uwyo.edu/rex/

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Centralized Data Management

• Expensive to maintain– Availability depends on central system

• Complex to ensure timely updates• Requires all participants to use compatible EHRs– Alternative is “interface engine”

• Requires ID number for all individuals• Complicates interoperability beyond state/region

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Federated Data Management

• “Network of networks”– Cross-state interoperability scales up– Record locator can use public information

• Local data is stored locally– Accessed only when needed for exchange– Providers/consumers determine what’s released– Data is as up to date as possible– Failure of a single system doesn’t affect others

Implementing a Federated Model• Web services support a lightweight mechanism for

exchanging information– Support distributing information in a variety of formats– Minimize the amount of maintenance to an entity’s

interface when others are added– Scale well when new systems are connected

• XML is used to describe a class of a data object and behavior of a program– Uses tags to surround the data to define and group data– Readable by both humans and computers

Implementing a Federated Model• Web Service Description Language– Describes the functions available and their interfaces– Describes the parameters that the functions are expecting

as well as the return types– File is usually put on a UDDI Directory Server advertising

the service• Web service runs on an accessible server– Service accepts a request for information and returns the

requested information– Messages are formatted according to the description file