Data for the paper entitled: Insecticide-treated bed nets and residual indoor spraying reduce malaria in areas with low transmission: a re-analysis of the Maltrials study. Taye Gari (1) and Bernt Lindtjørn (1,2*) 1 School of Public Health, Hawassa University, Hawassa, Ethiopia. 2 Centre for International Health, University of Bergen, Bergen, Norway. *corresponding author ORCHID Taye Gari; E-mail: tayegari@ymail.com; https://orcid.org/0000-0003-4091-4491 Bernt Lindtjørn; E-mail: bernt.lindtjorn@uib.no; https://orcid.org/0000-0002-6267-6984 Abstract Background: We reanalysed malaria incidence data from a malaria prevention study from the Rift Valley in Central Ethiopia. Our objective was to investigate if including an administrative structure within the society, which may have required consideration in our protocol or previous analysis, would provide divergent outcomes. Methods: We did a cluster-randomised controlled trial lasting 121 weeks with 176 clusters in four groups with 6071 households with 34,548 persons; the interventions combined Indoor Residual Spraying (IRS), and Insecticide-Treated Nets (ITN), IRS alone, ITN alone and routine use. The primary outcome was the malaria incidence. A multilevel negative binomial regression model was employed to examine the impact of the kebele and the proximity of homes to the primary mosquito breeding sites as potential residual confounders (levels). The study also assessed whether these factors influenced the effect measures of the interventions. Results: The initial findings of our study revealed 1183 instances of malaria episodes among 1059 persons, with comparable effects observed across the four intervention groups. In the reanalysis, the results showed that both ITN+IRS (incidence rate ratio [IRR] 0.63) and ITN alone (IRR 0.78) were associated with a greater reduction in malaria cases compared to IRS (IRR 0.90; P=0.28) or the control group (reference). The combined usage of IRS with ITN yields superior outcomes compared to the standalone use of ITN and surpasses the effectiveness of IRS in isolation. Conclusion: The findings indicate that implementing a combination of IRS and ITN decreased malaria incidence. Furthermore, there was an observed synergistic impact when ITN and IRS were used in combination. Considering relevant social structures as potential residual confounders is of paramount importance.   Variables: Variable Label Kebele Name of Kebele Ngare Numeric code of Gare Interv_arm Intervention arm to which gares are assigned Q102_Indiv~e Code of household members Q102_Name Name of household members _v1 Age in years AgeGroup Age group Q102_Sex Sex Q102_Relat~n Relationship Q102_Edu1e~d Education of HH head Q102_edu2_~l Formal education, HH head highest grade completed Q102_edu_h~l Education of all HH head categorized Q102_Occup Occupation Q102_Ethni~y Ethinicity Q102_relig~n Religion Wealth_index Wealth index in tertile,household RiskTim_la~i Risk time by last episode of malaria NumMalaria~2 Malaria episode by RDT (irrespective of species) from MalariaSta~2 Malaria status (dichotomized) by RDT (irrespective of pf_Onlyedit PF only (excluding mixed infections) pv_onlyedit PV only (excluding mixed infections) mixed Mixed infections Person_Yr_~p Person years last episode of malaria Person_Yr_~v Person years for post intervention Dist_From_~e Distance from the nearest vector breeding site in km Dist_Rec More or less than 1 km from the lake