This year, your county may have seen substantial changes in the rankings for Health Outcomes, Health Factors, or both as compared to last year. We anticipated that these changes might occur because one of the sources of information used to determine rankings has changed their methods. The Centers for Disease Control and Prevention (CDC) provides information from a survey called the Behavioral Risk Factor Surveillance System (BRFSS). The BRFSS informs the following Rankings measures: Health Outcomes (fair or poor health, mentally unhealthy days, and physically unhealthy days) and Health Factors (adult smoking and excessive drinking) measures. The CDC is using a new method to estimate these measures for your county. If you are interested in the technical aspects of this method, please see this article. This new method may lead to different estimates and ultimately may be what is driving the changes you see in your rank.
You may be wondering which estimates are “right” – the estimates from the 2015 rankings or the new estimates? Does the new method give us better estimates than before? The reality is that we can never truly know the right answers unless we could observe the behavior of every adult in the county. For example, to know the true percentage of adult smokers, we would need to determine the smoking status of every single adult in your area. This, however, would be difficult and costly. So, statistical methods are used to estimate the percentage of adult smokers in the community based on the information that is available. Each method used has benefits and drawbacks that are carefully considered in the context of the population sampled. It is most likely that the real numbers of your measures are somewhere in between last year’s and this year’s estimates.