2003 findings with survey instrument - Shadac

The goal of post-stratification is to adjust the person weights to match known population distributions ofa given group.Post-stratified Weight=(Basic person weight of the person in a group)*(Knownpopulation distribution for group/Sum of the basic person weights in a post-stratifiedgrouping)Post-stratifying the basic person weights ensures that the sum of person weights willequal known population distributions. For Indiana, the initial post-stratification sets thepopulation for each of the 10 geographic strata equal to the 2001 Census Bureaupopulation estimates for those areas (see Table A-4). In order to do this, respondents fromthe Hispanic surname stratum were merged in with the other 10 geographic strata basedon the county in which they reported living. Also, those respondents that reported livingin a geographic stratum that was different from the one used to draw their telephonenumber into the sample, were assigned to the geographic stratum that they reported livingin during the survey interview 13 .Two additional post-stratification adjustments were made to the data. The first used the 2002 CurrentPopulation Survey’s Annual Demographic Supplement (CPS-ADS) estimate of the number of peoplewithout phones in Indiana to perform the non-telephone coverage adjustment on the data. The basicassumption is that those people who lacked phone service for a week or longer during the past yearare very similar to those who do not have service. People who did not lack phone service differ withrespect to health insurance coverage from those who did or those who did not have phones at all.Thus, the 5.3 percent of people in Indiana who live in households without phone service, are added tothe weight total of those who lacked phone service for a week or longer (see Davern, et al. 2002 for adetailed description of this technique as applied to a state survey of health insurance coverage).The final post-stratification adjustment set the percent of Black/African American, and the percentHispanic to the 2001 Census Supplementary Survey (CSS) control percentages. According to the 2001 CSSBlack/African Americans make up 8.6 percent of the population and Hispanics make up 3.6 percent.Table A-4. 2001 Population Estimates for the Ten Geographic Regions in IndianaStratum2001 Population EstimateRegion 1 682,594Region 2 741,789Region 3 695,817Region 4 345,547Region 5 1,523,029Region 6 655,589Region 7 337,211Region 8 497,522Region 9 456,509Region 10 223,461Total 6,159,068Source: Census population estimates, July 200113 The self-reported geography of residence is superior to the one assigned by Genesys Marketing Systems Group because telephone areacode + exchange combinations cross geographic boundaries used to draw the initial sample, and therefore the self-report is consideredmore reliable and was used for analyses.32