At its core, hData is a simple way of organizing data into small pieces in folders, with a corresponding set of XML Schema to describe the small pieces. Because of this simplicity, it is easy to exchange information using hData. Currently hData can exchange data through two mechanisms:

1. RESTful Services - A Health IT system may provide RESTful web services to access hData.
2. Zip File - All of the information to be contained in an hData Record can be Zip filed. That Zip file can then be emailed, placed on a USB thumb drive, etc.

hData is a free open source XML standards project; there is no cost to use the hData XML schema.

hData is licensed under the Apache 2.0 open source license.

We will be submitting hData to a standards organization. We are careful selecting an organization that has a favorable intellectual property rights scheme. We want to guarantee royalty free access to hData. Until then, the hData standard remains the property of The MITRE Corporation, with all rights reserved.

Code contributions will be accepted to hData as bug fixes and new feature proposals.

hData is built using XML, using W3C XML Schema to specify the grammar. The structure of hData closely resembles the OpenDocument Format.

hData can be used to meet a number of health data needs, but initially, we are focusing on Continuity of Care. As such, much of the data vocabularies defined in hData model themselves after the HL7 CCD and ASTM CCR.

No. hData can be used by anyone interested in working with Health IT systems. hData is designed to make implementation fast and simple. Its simple serialization format and RESTful API make hData highly portable as well. While an obvious use of hData would be to expose the information stored in an EHR System, we hope that it will ease the development of all health applications by lowering the barrier to creating and consuming health data.

hData is based on XML, so it can be used with virtually any programming language. The MITRE team is working on developer kits in Ruby and Java. The hData project will gladly accept any contributions for generating or consuming hData in other programming languages.

Electronic documentation of health care data is currently at the heart of the U.S. national discussion on healthcare reform. Electronic health records (EHRs) have the potential to increase physician efficiency, reduce costs, and promote standardized care. However, health data exchange interoperability and other usability issues have plagued system-wide adoption and have thus limited the expected benefits. hData offers a solution to these problems by using a simple XML framework for the creation, storage, and exchange of health data.

Standards development of EHRs began with Health Level Seven (HL7) in the late 1980s. HL7, comprised of healthcare subject matter experts and information scientists, developed standards for the exchange, management, and integration of electronic healthcare information. The group first created the clinical document architecture (CDA), which was designed to address most of the documentation needs of any health care system. Consequently, this approach made the schema extremely flexible but overly complex, hard to implement interoperably, and difficult to manage. Around the same time, in a separate effort, a simplified continuity of care record (CCR)--not based on the CDA-- was created. Eventually, ASTM International, a highly regarded standards organization, adopted the CCR as its continuity of care record standard.

Later, HL7 reconciled its standards with ASTM by taking data elements from the CCR and encoding them in the CDA, resulting in a new standard called the Continuity of Care Document (CCD). The American National Standards Institute (ANSI) and its affiliated Health Information Technology Standards Panel (HITSP) recommended the CCD as an input standard for creating a national continuity of care standard. The result was initially published as the HITSP Construct 32 standard (C32), which has since expanded and grown more complex.

CDA, C32, and related standards contain a number of significant shortfalls. These include the repeated use of overly abstract data structures and underspecified implementation, including lack of normative schema, lack of a clearly profiled code system, and imprecise data types. HITSP has recognized the complexity of these existing standards and completed an effort to “streamline” documentation on how to use them. However, while this document reordering may provide some help, exchanging continuity of care information will still take place in the same overly complex format, and the entire existing HITSP framework is not always able to deliver a comprehensive, interoperable set of specifications.

hData was created to address these shortcomings. hData lowers the barrier to Health IT integration by focusing on ease of implementation.

hData is a contraction of “health” and “Data;” with the capital “D” emphasizing the core importance of data. The hData team's goal is to make the creation, exchange, consumption, and storage of health data simple, secure, and private. As a result, we believe better health outcomes are sure to follow.