Practitioners utilizing an address-based sampling frame for a self-administered, mail contact survey must decide on how to handle drop points, which are single delivery points or receptacles that service multiple households. A variety of strategies have been adopted, including sampling all units at the drop point or subsampling just one (or a portion) of them. This paper reports results from an experiment fielded during the 2021 Healthy Chicago Survey aimed at providing insight into whether there are any substantive differences between these approaches. We find that a subsampling strategy in which a single mailing is sent produces a roughly 3 percentage point higher response rate relative to a strategy sending multiple mailings concurrently to the drop point. While base-weighted distributions of gender and age differed enough to be statistically significant, there were no noteworthy differences across other demographics or across the base-weighted distributions of select key health outcomes measured by the survey. Taken together, these results provide some evidence that a “mail to one” drop point strategy is more efficient than a “mail to all” drop point strategy.

Most addresses on modern address-based sampling frames derived from the U.S. Postal Service’s Computerized Delivery Sequence file have a one-to-one relationship with a household. Some addresses, however, are associated with multiple households. These addresses are referred to as drop points, and the households therein are referred to as drop point units (DPUs). DPUs pose a challenge for self-administered surveys because no apartment number or unit designation is available, making it impossible to send targeted correspondence. The authors evaluate a method for substituting sampled DPUs with similar non-DPUs, which was implemented in the 2021 Healthy Chicago Survey alongside a concurrent survey of the originally sampled DPUs. Comparing aggregate distributions of DPUs and the non-DPU substitutes, the authors observe certain differences with respect to age, employment status, marital status, and housing tenure but no substantive differences in key health outcomes measured by the survey.

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