The effect of postcard reminders on vaccinations among the elderly: a block-randomized experiment

In: Behavioural public policy: BPP, Band 7, Heft 2, S. 240-265

Abstract

AbstractPrior research in the behavioral sciences has demonstrated that reminders can be an effective tool for encouraging health-related behavior changes. This article extends that literature by reporting the outcome of a randomized controlled trial of mailed vaccination reminders. In addition to making a substantive contribution regarding the efficacy of mailed reminders, this article also makes a methodological contribution: it illustrates how researchers can study the causal impact of an intervention even when a pure parallel trial is not possible. In this study, the Louisiana Department of Health sent postcard reminders regarding four recommended vaccinations (influenza, tetanus, shingles and pneumonia) to 208,867 senior residents of Louisiana. We used block randomization and a stepped wedge design to assess the efficacy of the intervention. Individuals were blocked by their prior vaccine record and randomized to receive the postcard in one of four consecutive months (October–January). The reminder postcard had an overall positive effect on vaccination rates. The statistically significant and substantively small increase in overall vaccination rates was driven by participants who received the postcard reminder early in the intervention period.