From the 1980s to 2010, CDC used a statistical method called post stratification to weight BRFSS survey data to known proportions of age, race and ethnicity, sex, and geographic region within a population. In 2011, the BRFSS moved to a new weighting methodology known as iterative proportional fitting or raking. Raking has several advantages over post stratification. First, it allows the introduction of more demographic variables, such as education level, marital status, and home ownership, into the statistical weighting process than would have been possible with post stratification. This advantage reduces the potential for bias and increases the representativeness of estimates. Second, raking allows for the incorporation of a now‐crucial variable, telephone ownership (landline and/or cellular telephone), into the BRFSS weighting methodology.
Beginning with the 2011 dataset, raking succeeded post stratification as the BRFSS statistical weighting method. As noted, age, sex, categories of ethnicity, geographic regions within states, marital status, education level, home ownership and type of phone ownership are currently used to weight BRFSS data.