Survey Methodology
The 2011 Colorado Health Access Survey (CHAS) is a program of The Colorado Trust. The Colorado Health Institute (CHI) managed the data collection and analysis of CHAS.
The survey was conducted via a random-digit-dialing, computer-assisted telephone interview by Social Science Research Solutions, an independent research company between May 10 and August 14, 2011. A representative sample of 10,352 households participated in the survey.
Of the 10,352 interviews, 1,214 were conducted with respondents who owned only a cell phone. This compares with a representative sample of 10,090 households surveyed from November 12, 2008, through March 13, 2009, for the 2008-2009 Colorado Household Survey. In the 2008-2009 survey, 400 interviews were conducted with respondents who owned only a cell phone. (NOTE: The name was changed for the 2011 survey and will remain the Colorado Health Access Survey in future surveys.)
Interviews were stratified by 21 Health Statistics Regions (HSRs) in Colorado to ensure adequate representation within each of them. These are the 21 HSRs developed by the Colorado Department of Public Health and Environment for public health planning purposes. Regions with sufficient numbers of African American households were oversampled to ensure an adequate sample of African Americans comparable to their proportion in the Colorado population.
Survey data were weighted to 1) adjust for the fact that not all survey respondents were selected with the same probability, and to 2) account for gaps in coverage in the survey frame. Because of this weighting process, CHI refers to the people who answered the questions as “respondents.” But when discussing results, which have been weighted to the Colorado population, CHI refers to “Coloradans.”