Data, Data Everywhere

There's hardly a health story out there that cannot benefit from some good data – from estimates of the number of elderly Americans to hospital quality ratings for your community.

This article will help you find useful databases and offer guidance on how to use them accurately. The first part will focus on population counts and characteristics from the Census Bureau. The second part will explore databases specifically about health and medicine.

The Census Bureau's basic mission is to count every American, offer detailed portraits of their demographic, social, economic and housing characteristics, and update that information every year. Census Bureau numbers offer something for many beats: They let you assemble a broad portrait of a community, as well as compare your area with the nation. And, officially speaking, population figures are part of the raw material used to construct birth rates, disease rates and death rates.

On the Census Bureau website, I want to recommend that you look at the Newsroom toward the bottom of the Web page, which offers links to recent news releases. You can sort by topic to find the most recent ones.

To dig in more deeply, I recommend you become familiar with the bureau's annual population estimates by age, race/Hispanic origin and sex, and the American Community Survey. The population estimates can help you find the fastest-growing community in your state, the place with the largest Hispanic population or the area with the most elderly women, for example - all of them potential targets for health programs and topics of stories.

The American Community Survey

The American Community Survey can get you more specific data on the characteristics of people, especially the needy or vulnerable. You also can compare characteristics of men and women, as well as race, ethnic and age groups. The ACS, as it's known for short, is a monthly household survey that asks questions similar to those on the census long form, which it replaced in 2010. The topics it covers include household type (such as married, single-parent, living alone), education level, immigration, income, commute time and type, employment, home size and value, amount of mortgage or rent, and more. Disability status, based on self-ratings, also is available for adults and children. Starting with 2008 data, which will be released in 2009, the survey will include information on health insurance coverage status.

All ACS estimates are available for the nation, states, counties and other levels of geography (such as metropolitan areas and school districts) with at least 65,000 people. Data for smaller areas will be available in the future.

The ACS could be useful if you are doing a story about immigrant health services and want to know how many immigrants live in a particular area, where they come from, and how well they speak English. Or perhaps you want to find out about the number and kind of people who do not own cars, which could affect their ability to get to medical treatment. Or maybe you'd like to know about single-parent households.

But there are topics that the Census Bureau does not ask about. They include religion, political party, crime victimization and home schooling. Nor does the Census Bureau ask directly about sexual orientation, although it gives people the option of saying they live with an unmarried partner. An estimate of same-sex couples can be derived from that, though that is only part of the gay and lesbian population.

An additional caution is that the survey uses estimates, and therefore there is a margin of error, as there is with any survey. The Census Bureau displays the margin of error, and you need to consider it because, because you don't want to draw conclusions that might be inaccurate. This is especially true if you are dealing with small population groups (which have large margins of error) or trying to compare different groups or places.

To help you visualize how to find something, I've prepared a set of slides that walk you through how to locate a particular set of estimates – in this case, information about immigrants in Los Angeles. [Ed. note: Click on the link in the righthand column.] This provides a limited look at what the survey can do. For example, you can rank the 50 states by the share of immigrants born in Asia, or rank Congressional districts within one state by the share of people over 65 who live there.

There is a user guide for the ACS; on the Census Bureau web site, including one especially for the media. Each state also has an official state data center that is supposed to help people find and use census numbers. Some of these agencies are better than others. Here is a link to the state data centers page.

Other useful Web sites

Let me mention also a few groups that use and analyze census data in easy-to-understand ways. Some of their websites are simpler to use than the Census Bureau's, especially if you are looking for just one number. The KidsCount project, funded by the Annie E. Casey Foundation, gathers material from a variety of sources about child well-being, such as health, education and family circumstances. The Migration Policy Institute's Data Hub offers detail about immigrants in the U.S. (and in other countries), if that is your focus. The Pew Hispanic Center has a particular focus on Latinos, but also tracks general demographics. All three are nonpartisan groups and don't take advocacy positions.

Now let's look at some health-specific databases. Much of what is out there is on government websites. There is the National Center for Health Statistics, which compiles the nation's official vital statistics (births, deaths, marriages), but also has information on infant mortality, the National Health Interview Survey (health behavior or status) and other topics. It can be difficult to navigate, but there is a site index that lets you browse topics.

One database that is derived from government data, but not run by the government, is the Dartmouth Atlas of Health Care. It uses Medicare data to explore disparities in medical care, health costs and hospital performance at the national, state and local level. The site lets you look at Medicare data for hospitals – one hospital, a hospital region, all the hospitals in a state – to make comparisons. The Dartmouth researchers contend that there are many hospitals or physicians providing too much expensive care that does not produce better results than lower levels of care.

The U.S. Department of Health and Human Services also offers a tool to compare hospitals by patient satisfaction ratings, quality of care, outcomes and Medicare payments. It's called Hospital Compare, and covers a growing pool of hospitals, though not all of them yet (for example, psychiatric and rehabilitation hospitals were not included as of October 2008). Another problem is that hospital participation is voluntary.

More data about quality and disparity can be found on the website of the Agency for Health Research and Quality. This agency regularly publishes a national health care quality report, with state tables, and a national health disparity report, with comparisons. You can look, for example, at racial gaps in appropriate treatment. The agency also offers state snapshots that can tell you the best and worst quality measures in a particular state.

On the right side of this page, under the heading Useful Resources from the Web, you'll find a longer list of demographic and health data sources that I've put together, with links, because there are so many good ones available. Health reporters are fortunate to have so much data out there, in increasingly accessible form, with more on the way.

D'Vera Cohn, a former reporter for the Washington Post, is senior writer for demographics and health trends for the Pew Research Center in Washington, D.C.