4.13: Secondary Data
- Page ID
- 116200
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)In addition to vital statistics (birth and death records) and other primary sources of public health data, there are many other places that public health people can go to look for relevant statistics.
Here are a few of them.
- Secondary data means data collected by someone else, possibly for another purpose
- Useful in planning of public heath programs and facilities
- U.S. Census
- Enumeration of the population
- Taken every 10 years
- Gathers data on race, age, income, employment, education, dwelling type, other
- Statistical Abstract of the United States
- Book published annually by Bureau of Census
- Summary of statistics on social, political, and economic organization of the United States
- Monthly Vital Statistics Report
- Vital statistics are summaries of records of major life events: birth, death, marriage, divorce
- Published by National Center for Health Statistics under the CDC
- Also calculates death rates by race and age
- Morbidity and Mortality Weekly Report (MMWR)
- Prepared by CDC from state health department reports
- Reports morbidity and mortality data by state and region of U.S.
- Reports outbreaks of disease, environmental hazards, unusual cases, or other public health problems
For our purposes, you don't need to memorize each of these sources. Rather, they can give you an idea where to lookwhen you are researching a health topic -- you can ask a librarian for help with accessing these sources. They also can help you to be a more critical consumer of information. When you see a headline about some new statistic, you can ask, where did that come from? Is in Census data? Is it from an analysis of the notifiable disease records? Is it survey data?
National health surveys are -- as their name says -- national in scope. There are many other kinds of surveys also available, in epidemiological studies (discussed below) or other kinds of studies (sociological, psychological, economic, etc.). The national health surveys are repeated on a regular basis, which makes it easier to detect changes in population health.
The National Health Survey Act of 1956 authorized continuing survey of amount, distribution, and effects of illness and disability in the U.S. These include three types of surveys or data collection:
- Health interviews of people
- Clinical tests, measurements, and physical examinations
- Surveys of places where people receive medical care
Some examples of national health surveys include
- National Health Interview Survey (NHIS)
- National Health and Nutrition Examination Survey (NHANES)
- Behavioral Risk Factor Surveillance System (BRFSS)
- National Health Care Survey (NHCS)
The data from these national health surveys is now available on the Internet - you can see summaries of their findings, reports, graphs, statistics, or even (in some cases) the data sets themselves. Of note, some of these studies (like the Behavioral Risk Factor Surveillance System) have been paused, ended or substantially altered in 2025, so up-to-date data on youth risk behaviors may not be as easily available in the future.
Figure \(\PageIndex{1}\): Often the data from these surveys is combined with mapping information to create maps -- like we saw in the Unnatural Causes video. Here's an example showing health survey data and a map of San Francisco. (Public domain; City and County of San Francisco, www.thehdmt.org)