Sampling frame

A sampling frame is the operational list or other device identifying the units from which a statistical sample can be selected. The intended statistical population, the sampling frame and the responding units can differ. A register of residential addresses, for example, can serve as a sampling frame for a household survey, but may miss newly built homes and include demolished buildings.

If 100 of 1000 target households are absent from the sampling frame, randomly selecting 90 of the 900 listed households gives each listed household inclusion probability $0.1$ and each omitted household inclusion probability zero. Increasing the sample among listed households cannot by itself correct that lack of coverage. Duplicate entries create a different problem: units with more entries can be more likely to be selected. A sound design therefore documents how frame units map to population units and distinguishes coverage errors from sampling variability.