biostudies-literatureWilliams NJNIMH NIH HHSNational Institute of Mental Health66https://www.ebi.ac.uk/biostudies/studies/S-EPMC9526963biostudies-literatureUnknown17(1)<h4>Background</h4>Statistical tests of mediation are important for advancing implementation science; however, little research has examined the sample sizes needed to detect mediation in 3-level designs (e.g., organization, provider, patient) that are common in implementation research. Using a generalizable Monte Carlo simulation method, this paper examines the sample sizes required to detect mediation in 3-level designs under a range of conditions plausible for implementation studies.<h4>Method</h4>Statistical power was estimated for 17,496 3-level mediation designs in which the independent variable (X) resided at the highest cluster level (e.g., organization), the mediator (M) resided at the intermediate nested level (e.g., provider), and the outcome (Y) resided at the lowest nested leveImplementation science : ISRequired sample size to detect mediation in 3-level implementation studies.PMC9526963P50MH113840Williams NJMandell DSAllison PDPreacher KJMarcus SCfalseRequired sample size to detect mediation in 3-level implementation studies.<h4>Background</h4>Statistical tests of mediation are important for advancing implementation science; however, little research has examined the sample sizes needed to detect mediation in 3-level designs (e.g., organization, provider, patient) that are common in implementation research. Using a generalizable Monte Carlo simulation method, this paper examines the sample sizes required to detect mediation in 3-level designs under a range of conditions plausible for implementation studies.<h4>Method</h4>Statistical power was estimated for 17,496 3-level mediation designs in which the independent variable (X) resided at the highest cluster level (e.g., organization), the mediator (M) resided at the intermediate nested level (e.g., provider), and the outcome (Y) resided at the lowest nested leve2022-01-01T00:00:00Z2022 Oct2025-04-26T11:58:00.307Z2025-04-06T13:51:44.715ZS-EPMC95269633618309010.1186/s13012-022-01235-2