Alam 1989 BGD.

Methods	CBA study
Participants	Number: 623 children (after excluded 27 in intervention group and 50 in control group) Inclusion criteria: HHs with children aged 6–23 months, with > 6 months' observations per year
Interventions	Intervention site (3 subunits): hand pumps were provided with a ratio of 4–6 HHs (3 times more than control) + health education (main objectives: promotion of consistent and exclusive use of hand pump water, improvement of water handling and storage practices, disposal of child's faeces soon after defecation, washing hands before handling food and rubbing hands in ash or using soap after defecation). Control site (2 subunits): no project input.
Outcomes	Incidence of diarrhoea among children aged 6–23 months. Diarrhoea: ≥ 3 loose motions in 24‐hour period whether or not blood was present. An episode was considered new if there was an interval of ≥ 48 hours between symptoms (recall = 7 days). Observed sources of water, faeces visible in the yard, handwashing before food and after defecation
Notes	Location: 5 subunits (paras) in a village in rural Bangladesh Length: 3 years (July 1980 to June 1983) Publication status: journal
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Allocation not random.
Allocation concealment (selection bias)	High risk	No allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	NA
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	NA
Incomplete outcome data (attrition bias) All outcomes	Low risk	Similar number of child‐periods excluded in the analysis in both groups (54 vs 55).
Selective reporting (reporting bias)	Low risk	Report on outcomes prespecified in methods.
Other bias	Unclear risk	‐
Similarity of baseline outcome measurements	Unclear risk	No mention of baseline risk.
Similarity of baseline characteristics	Unclear risk	The intervention and control "populations were comparable in terms of education, HH size and sanitation conditions". but no data presented).
Adequate allocation of intervention concealment during the study	High risk	Quote: "Workers' knowledge of which area was intervention and control."
Adequate protection against contamination	High risk	Allocation by community – adjacent paras and in the control group some HHs installed hand pumps. Quote: "Over the years of the project some households in the control area purchased their own hand pumps privately."
Confounders adequately adjusted for in analysis/design	High risk	No analysis adjusting for confounders.
Recruitment bias	Unclear risk	NA
Baseline imbalance	Unclear risk	NA
Loss of clusters	Unclear risk	NA
Incorrect analysis	Unclear risk	NA