Coverage measurement is an important aspect of national surveys and program evaluations targeting specific populations and sub-populations. Coverage is especially important on studies focused around vulnerable or hard to reach populations or on studies where the sample frame has known deficiencies. NORC employs a number of techniques for assessing coverage measurement, including comparisons of age distributions in household rosters with age distributions in the decennial census or ongoing census surveys, extensive examination and testing of sampling frames, consultation with experts, follow-up efforts to collect limited data, capture/recapture techniques, and monitoring of sample characteristics against initial assumptions.
NORC has conducted extensive research and incorporated into our area probability surveys the U.S. Postal Service address list as a National Frame to improve coverage for surveys.