Optimized probability sampling of study sites to improve generalizability in a multisite intervention trial.

INTRODUCTION: Studies of type 2 translation, the adaption of evidence-based interventions to real-world settings, should include representative study sites and staff to improve external validity. Sites for such studies are, however, often selected by convenience sampling, which limits generalizability. We used an optimized probability sampling protocol to select an unbiased, representative sample of study sites to prepare for a randomized trial of a weight loss intervention. METHODS: We invited North Carolina health departments within 200 miles of the research center to participate (N = 81). Of the 43 health departments that were eligible, 30 were interested in participating. To select a representative and feasible sample of 6 health departments that met inclusion criteria, we generated all combinations of 6 from the 30 health departments that were eligible and interested. From the subset of combinations that met inclusion criteria, we selected 1 at random. RESULTS: Of 593,775 possible combinations of 6 counties, 15,177 (3%) met inclusion criteria. Sites in the selected subset were similar to all eligible sites in terms of health department characteristics and county demographics. CONCLUSION: Optimized probability sampling improved generalizability by ensuring an unbiased and representative sample of study sites.

Maternal mental health and the persistence of food insecurity in poor rural families.

BACKGROUND: Little is known about the causal relationship between and the mechanisms linking depression and food insecurity. Our purpose was to examine these knowledge gaps. METHODS: Chi-squared analysis of longitudinal data from 29 rural upstate New York families followed for three years and qualitative analysis of interviews were used to identify associations and mechanisms. RESULTS: Depressive symptoms (p=.009) and poor mental health (p=.01) in mothers limited the likelihood families would leave food insecurity. This relationship was mediated through limiting the employment of adult family members and operated in three ways: preventing the depressed household member from working, preventing a different household member from working, and limiting access to childcare for depressed children so adults could work. CONCLUSIONS: Poor mental health is associated with keeping families food-insecure by limiting their employment. High-quality, accessible mental health care is needed for poverty-associated food insecurity to be alleviated.