Keating 2011.

Methods	Study design: cRCT with 2 intervention arms Unit of allocation: clusters (villages) Number of units: 58 randomized villages in each arm Outcome assessment/surveillance type: 15 houses within each village were randomly selected to serve as ultimate sampling units, giving 870 houses in each arm of the study. Household residents were given a questionnaire and took a RDT (Carestart) for malaria infection. Positive tests were confirmed by blood smear microscopy. Length of follow‐up: 3–4 months post spraying (6–15 October 2009) Adjustment for clustering: yes
Participants	Number of participants: 7273 resided in participating houses. In the paper, 5508 total from Table 2 but 5502 stated in results Population characteristics: the distribution of participants living in houses located in treatment and control villages was similar on sex, age, employment status of the respondent, and education level Withdrawal and loss to follow‐up: test refusal rates differed between treatment (8.5%) and control (12.7%) arms (P < 0.05)
Interventions	Comparison: IRS + ITN versus ITN alone IRS: Active ingredient and dosage: DDT 1–2 g/m² Formulation: wettable powder Frequency of spraying: once, June–July 2009 Coverage: minimum 80% target (84.8% of households sampled sprayed within 12 months) Buffer size between clusters: > 5 km between intervention and control villages. in 2 instances whereby a treatment village was too close (< 5 km) to a control village, the closest village > 5 km was selected into the control arm. ITN: any ITN that was treated at least once in last 11 months, or was an LLIN Coverage: measured as people living in household owning ≥ 1 ITN: 75.8% (range 74.2% to 77.4%) Compliance: measured as individuals using ITN in the previous night: 50.7% (range 48.6% to 52.8%) Control: ITN only as above Coverage: measured as people living in household owning ≥ 1 ITN: 72.0% (range 70.2% to 73.7%) Compliance: measured as people using ITN in the previous night: 46.2% (range 43.9% to 48.6%) Cointerventions: larval habitat management and continued case management
Outcomes	Malaria prevalence: parasite infection and febrile illness data from all household residents > 1 month old requiring a positive RDT (Carestart) and a positive thick blood film
Location profile	Study location: Gash Barka, West lowlands of Eritrea, mostly rural and agricultural. Altitudes were 1500–3000 m above sea level. 30% of the country's population lived here. Approximately 200 mm per year precipitation. Temperatures were extremely hot and dry climatic conditions with seasonal precipitation, concentrated in the summer months. Malaria endemicity: season with peak transmission occurring September–November. Smaller malaria season March–April EIR: study references an estimated annual range of 0–70.6 (Shililu 2004). Population proximity/density: not reported Plasmodiumspp:P falciparum with rare reports of P vivax
Vector profile	Primary (and secondary) vector species:An arabiensis and An gambiae s.s. Vector behaviour (nature, stability, adult habitat, peak biting times, exophilic/endophilic, exophagic/endophagic, anthropophilic/zoophilic): not reported Phenotypic resistance profile: not reported Genotypic resistance profile: not reported Method of mosquito collection: no entomological data collected
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Fifty‐eight (58) villages within Gash Barka were randomly…" Comment: however randomization procedure was not described.
Allocation concealment (selection bias)	Unclear risk	Not stated.
Blinding of participants and personnel (performance bias) Incidence of malaria	Low risk	Outcome not reported.
Blinding of participants and personnel (performance bias) Prevalence of malaria	Low risk	Participants and personnel were not blinded to the intervention status; however, the outcome would not be affected by this knowledge.
Blinding of outcome assessment (detection bias) Incidence of malaria	Low risk	Outcome not reported.
Blinding of outcome assessment (detection bias) Prevalence of malaria	Low risk	Outcome assessors were not blinded to the intervention status; however, the outcome was measured using an objective tool (Carestart RDT) and would not be affected by this knowledge.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Only one time point used, inapplicable
Selective reporting (reporting bias)	Low risk	The study only intended to report the relationship between IRS and parasite prevalence and this outcome was provided. Numbers appeared correct, assumed typographical error in table 2, should read 5502.
Recruitment bias	Low risk	Households for survey were randomly selected.
Baseline imbalance	Unclear risk	Baseline data were not displayed but due to randomization this should be accounted for.
Loss of clusters	Low risk	No mention of lost clusters.
Incorrect analysis	Low risk	Adjustment for clustering was done.
Comparability with RCTs randomizing participants	Low risk	Because the intervention is expected to have community level impact as well as individual impact, cRCTs are the most appropriate study design to capture this.
Other bias	Low risk	No other biases.