About the Data
The Behavioral Risk Factor Surveillance System (BRFSS) is a telephone health survey of adults 18 and older, conducted in all U.S. states and territories. 

Limitations
BRFSS data is subject to numerous limitations, similar to any population-based survey. Participation in the BRFSS is voluntary and the data is self-reported, which can lead to non-response, recall, and social desirability bias (when people tend to answer questions in a way that they think will be viewed favorably by others, rather than giving honest or accurate responses). Furthermore, the BRFSS only targets non-institutionalized adults who are able to complete the interview unassisted by telephone in English or Spanish. Lastly, there may be a small sample for some populations, resulting in data suppression or instability. See comments on graph for sample size.

For additional information about the Nebraska BRFSS, please visit their website.