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Gregory Knell, Deborah Salvo, Kerem Shuval, Casey Durand, Harold W. Kohl III and Kelley P. Gabriel

Recent technological advances allow for field-based data collection of accelerometers in community-based studies. Mail-based administration can markedly reduce the cost and logistic challenges and burden associated with in-person data collection. It necessitates, however, other resources, such as phone calls and mailed reminder prompts, to increase protocol compliance and data recovery. Additionally, lost accelerometers can impact the study’s budget and its internal validity due to missing data. In this article, we present an applied methodological approach used to define thresholds (or cutoff points) at which pursuing unreturned accelerometers is a worthwhile versus futile pursuit. This methodological approach was designed, specifically, to maximize scalability across multiple sectors. We used data from an on-going study that administered accelerometers through the mail to illustrate and encourage investigators to replicate the approach for use in their own studies. In heterogeneous study samples, investigators might consider repeating this approach by study-relevant strata to refine thresholds and improve the return percentages of data collection instruments, minimize the potential missing data, and optimize study staff time and resources.

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Gregory Knell, Henry S. Brown, Kelley P. Gabriel, Casey P. Durand, Kerem Shuval, Deborah Salvo and Harold W. Kohl III

Background: Improving sidewalks may encourage physical activity by providing safe, defined, and connected walking spaces. However, it is unknown if reduced health care expenditures assumed by increased physical activity offset the investment for sidewalk improvements. Methods: This cost-effectiveness analysis of sidewalk improvements in Houston, TX, was among adults enrolled in the Houston Travel-Related Activity in Neighborhoods Study, 2013–2017 . The 1-year change in physical activity was measured using self-report (n = 430) and accelerometry (n = 228) and expressed in metabolic equivalent (MET) hours per year (MET·h·y−1). Cost-effectiveness ratios were calculated by comparing annualized sidewalk improvement costs (per person) with 1-year changes in physical activity. Results: The estimated cost-effectiveness ratio were $0.01 and −$0.46 per MET·h·y−1 for self-reported and accelerometer-derived physical activity, respectively. The cost-effectiveness benchmark was $0.18 (95% confidence interval, $0.06–$0.43) per MET·h·y−1 gained based on the volume of physical activity necessary to avoid health care costs. Conclusions: Improving sidewalks was cost-effective based on self-reported physical activity, but not cost-effective based on accelerometry. Study findings suggest that improving sidewalks may not be a sufficient catalyst for changing total physical activity; however, other benefits of making sidewalks more walkable should be considered when deciding to invest in sidewalk improvements.