Power Analysis and Sample Size Calculation for Semi-Field Vector Control Trials R package simpowa version 1.0.3 Uses simulations from generalized linear mixed-effects models to incorporate random effects across multiple sources and levels of variation, and a dispersion parameter to account for overdispersion and capture unexplained variability. Covers design scenarios for both short-term and long-term trials evaluating the impact of single or combined vector control interventions. Methods build on Kipingu et al. (2025) <doi:10.1186/s12936-025-05454-y> and Johnson et al. (2015) <doi:10.1111/2041-210X.12306>. Software Imports: lme4, parallel, dplyr, ggplot2, stats Suggests: rmarkdown, testthat (>= 3.0.0), waldo, devtools Andrea M. Kipingu <akipingu@ihi.or.tz> Comprehensive R Archive Network (CRAN) Andrea M. Kipingu [aut, cre] (ORCID: <https://orcid.org/0000-0002-9063-8651>, affiliation: Environmental Health & Ecological Sciences Department, Ifakara Health Institute, P.O. Box 78 373, Dar es Salaam, Tanzania), Mafalda Viana [aut] (ORCID: <https://orcid.org/0000-0001-5975-6505>, affiliation: School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK), Paul C.D. Johnson [aut] (ORCID: <https://orcid.org/0000-0001-6663-7520>, affiliation: School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Wolfson Link Building, Glasgow, G12 8QQ, UK), Samson S. Kiware [aut] (ORCID: <https://orcid.org/0000-0001-7252-520X>, affiliation: Environmental Health & Ecological Sciences Department, Ifakara Health Institute, P.O. Box 78 373, Dar es Salaam, Tanzania) MIT + file LICENSE (https://CRAN.R-project.org/package=simpowa/LICENSE) 2026-03-29 application/tgz https://CRAN.R-project.org/package=simpowa doi:10.32614/CRAN.package.simpowa