Tracking Case Dispositions and Calculating Response Rates in the ACS Prepared for the September 26, 2006 meetings of the Federal-State Cooperative Program for Population Estimates

How does unit nonresponse and CAPI subsampling affect the confidence intervals?

What happens to the initial sample? Factors that reduce the sample size from the initial sample –Survey nonresponse –Identification of sample addresses that are ineligible for interviewing –CAPI subsampling –Availability of “good” phone numbers

Response Rate Ratio of weighted estimate of total interviews to weighted estimate of eligible universe Weighted estimate of the eligible universe is the initial sample minus the weighted estimate of deletes (e.g., commercial, nonexistent, not a housing unit)

Example 1 - statistics Initial sample10,000 Percent unmailable10% Response rate97.6% Final interviews7079 (70.8%)

Example 2 - statistics Initial sample10,000 Percent unmailable50% Response rate96.4% Final interviews6601 (66.0%)

Impact of unmailables on final sample State Unmailable Rate Ratio of final interviews to initial sample Alaska29%59% Maine33%61% Puerto Rico28%60% Wisconsin2%74% Iowa1%74% Ohio1%72%

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