This document examines whether post-stratification adjustments can correct for bias in traditional landline telephone surveys that do not sample cell phone-only households. The author analyzes health-related estimates from the 2007 National Health Interview Survey with and without cell phone-only households. Post-stratification weighting is applied to the non-cell phone-only subsample. Results show that post-stratification reduces bias compared to the original weights, though it increases variance slightly. The adjusted estimates are only modestly different from the total sample estimates. Therefore, post-stratification weighting can effectively correct for bias from excluding cell phone-only households in landline telephone surveys.

1. Can Post-Stratification Adjustments Correct Bias in Traditional RDD Estimates? Kathleen Thiede Call SHADAC AAPOR, Florida May 14, 2009 Funded by a grant from the Robert Wood Johnson Foundation

7. Table 1. Selected estimates with original public use weights by phone status Compared to NHIS non-elderly total sample, the non-CPOH subsample (B-A) significantly underestimates all key health related outcomes Non-CPOH and CPOH subsamples are significantly different on all health related estimates (B-C), with CPOH reporting higher rates on all outcomes