When Healthdata.gov launched, we were thrilled to see the Health Indicators Warehouse (HIW) listed as a featured site. HIW itself had gone live recently and interest has been strong and growing steadily.  Much of the interest is in the Application Programming Interface (API) available to HIW users. 

API OVERVIEW

Web services allow developers on different platforms to exchange or retrieve structured datasets, such as the data contained in the HIW. Once received, the data can be used immediately or reconstituted and integrated with other datasets, and then made available directly to new users.  The HIW API exposes data through two distinct service models:  one that follows the RESTful architectural style and one that adheres to the Simple Object Access Protocol (SOAP) specification.  The base URLs including the Web Service Definition Language (WSDL) for SOAP, service methods, and service return types can be found in the For Developers section of the HIW.

SOAP is a highly structured approach with commands and options determined by the data center providing access.  REST (Representation State Transfer) is a flexible approach using rich URLs to call resources from the target source.  By supplying services under both approaches, HIW seeks to allow third party developers to pick their preference.  By connecting to HIW, developers can use REST or SOAP services to build creative apps. 

HIW CONTENT OVERVIEW

The organizing concept for the HIW’s content is the indicator, simply a statement describing a way of measuring some characteristic or behavior.  In HIW, these include measures of the health of a population (such as life expectancy, mortality, disease incidence or prevalence, or other health states); determinants of health (such as health behaviors, health risk factors, physical environments, and socioeconomic environments); and health care access, quality, and use. 

Each indicator has descriptive metadata and data.  The metadata include the indicator name and description, references, selected evidence-based interventions, and the methods used to gather and process the data.  These valuable metadata are paired with the indicator data, which are the actual values of the measured characteristic.  This content is organized into various dimensions, such as age groupings, sex/gender, geographic location, and/or race/ethnicity.  The data also includes specifics about the years of data represented, the source and supplier of the data, response rate and sample size information, and other important details helpful to evaluate and use the indicators. All of this content can be pulled directly through the API.

APPLICATIONS

Using the APIs, developers access this metadata and data content and invent new applications for the information.  During a recent code-a-thon held by Health 2.0, one developer team combined data on food deserts with health outcomes data, raising awareness of needs and empowering users to improve available food choices. 

Another developer team designed myBlueMeter, a marriage of HIW and the Department of Veterans Affairs and the Centers for Medicare & Medicaid Services’ Blue Button.  With Blue Button, veterans and Medicare beneficiaries can download their health information.  With HIW, users can view national, state, or county benchmarks for many health indicators.  Within myBlueMeter, individuals can see how their personal health compares to their peers, and what action steps they can take to match or beat the health measure values of those peers.  The long term expectation is that this feedback will result in positive health behavior change.

Presentations of these and other apps using various data sources are available from the Health 2.0 Developer Challenge.  Our hope is that innovative developers will continue to create new applications as more data becomes available through the HIW and developers create mashups with increasing amounts of crowd sourced and locally available data.

LOOKING AHEAD

We continue to increase the documentation of our API, including the addition of release notes specific to the web services and the inclusion of code examples for C#, Visual Basic, JSON, and XML.  We invite your input and suggestions for how we can improve our documentation further, and of course we are interested in examples that have been built using the HIW API.

Healthdata.gov now has a new topic area in its Forum specifically to field questions from developers and to prompt discussions about using the HIW APIs.  Our developers will be responding to technical questions and providing tips and guidance on using the REST and SOAP services.  Your active participation will help us identify and prioritize any new services that will give all of us the biggest return on this investment.

Join the conversation at the Health Indicators Warehouse Forum.