Data Types - Screening and Risk Factors

Direct Estimates are the usual estimates reported from a survey–directly estimated from the survey data using appropriate weighting. Most of these direct estimates are based on data from the Behavioral Risk Factor Surveillance System (BRFSS), a large annual telephone survey of U.S. households designed to measure at the state level.

Bias-Adjusted Modeled Estimates combine results from BRFSS and the National Health Interview Survey (NHIS), a smaller, in-person survey, using a statistical model that takes advantage of the strengths of each survey. These estimates:

• adjust for biases inherent in BRFSS using NHIS, which has a better response rate and reaches houses without land-line telephones.
• smooth the results by applying data from demographically similar areas across the country.
• enable estimates for counties with few or no BRFSS respondents by using data from similar areas, albeit at the loss of specificity to that particular small area.
• pool data from multiple years to obtain more responses for small areas.
• can only be used when both surveys ask identical questions, so the number of statistics that can be modeled this way is limited.

See http://sae.cancer.gov for more details.

Summary of Available Statistics by Data Type

	Direct Estimates	Bias-Adjusted Modeled Estimates
Areas	States US	Counties States US
Time Period	Most current single year	Pooled years
Survey(s)	BRFSS (or CPS or ANR*)	BRFSS and NHIS combined
Topics Available	Clinical Breast Exam Fruit/Vegetable Servings Home Blood Stool Test Mammogram Overweight or Obese Pap Smear Physical Activity Signmoidoscopy or Colonoscopy Smokers Smoking Not Allowed and Smoking Laws (not based on BRFSS*)	Mammogram Pap Smear Smokers
Limitations	Telephone-only survey method introduces bias and inaccuracies (greater for some statistics than for others)	Depending on the local sample rate, estimates for small areas may not reflect local factors (such as a media campaign to promote mammograms)

* Smoking Not Allowed measures are direct estimates and are from the Current Population Survey (CPS) Tobacco Use Supplement. The data for Smoking Laws come from Americans for Nonsmokers’ Rights (ANR) and are based on analysis of laws across the country.

References

Bias-Adjusted Modeled Estimates (Small Area Estimates), National Cancer Institute
Behavioral Risk Factor Surveillance System, Centers for Disease Control and Prevention
National Health Interview Survey, Centers for Disease Control and Prevention
Current Population Survey Tobacco Use Supplement, National Cancer Institute and U.S. Census Bureau
U.S. Tobacco Control Laws Database©, Americans for Nonsmokers’ Rights Foundation