Kotch 2007 USA.

Methods	Cluster RCT
Participants	Number: 388 children Inclusion criteria: children were expected to remain assigned to the same classroom throughout the 7‐month study period and be 36 months of age at the end of data collection and that ≥ 1 family contact could participate in a telephone survey in English. Siblings were allowed to participate when they also attended the study centre and met the eligibility criteria. Intervention group: mean age of children = 21.26 months and 6.39 boys per class. Control group: mean age = 21.41 months and 3.61 boys per class.
Interventions	Intervention (23 childcare centres): staff were trained using the 'Keep It Clean' training module to improve and standardize the handwashing, sanitation, nappy changing, and food‐preparation procedures. Nappy changing, handwashing, and food‐preparation equipment with impermeable, seamless surfacing were provided. In addition, automatic faucets and foot‐activated, roll‐out waste bins for nappy disposal were provided. Control (23 childcare centres): staff were trained using the 'Keep It Clean' training module but received no equipment.
Outcomes	Severe diarrhoea incidence: any loose, watery stool that if contained would assume the shape of the container. A separate episode of diarrhoea was defined by an interval of 7 diarrhoea‐free days. Survey every 2 weeks. Number of days sick Number of days child absent for centre because of illness Number of days parents missed work because of child illness Sick days of caregivers in centres Nappy and food preparations practices
Notes	Location: 46 childcare centres in 21 counties, NC, USA Length of study: 7 months' follow‐up (December 2002 to July 2003) Publication status: journal
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: no details. Quote: "from each pair 1 centre was randomly selected as intervention centre."
Allocation concealment (selection bias)	Unclear risk	No details.
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No blinding specified although as the outcome was assessed by telephone by the survey research unit at UNC, it could have been blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	121 children LTFU from 388 children in total (31% LTFU) but the numbers were similar in intervention and control groups (59 control and 62 intervention LTFU, not significant).
Selective reporting (reporting bias)	Low risk	Report on prespecified outcomes in paper.
Other bias	Unclear risk	—
Similarity of baseline outcome measurements	Unclear risk	NA
Similarity of baseline characteristics	Unclear risk	NA
Adequate allocation of intervention concealment during the study	Unclear risk	NA
Adequate protection against contamination	Unclear risk	NA
Confounders adequately adjusted for in analysis/design	Unclear risk	NA
Recruitment bias	High risk	Appeared the directors recruiting the children were aware of which cluster the centre was in.
Baseline imbalance	High risk	Baseline imbalances in mean classroom enrolment, mean number of children participating in the study per classroom, mean number of boys enrolled in the classroom, and mean number of boys participating in the study per classroom. Because the direction of the differences, more boys and more total children in intervention classrooms and did not adjust in analysis.
Loss of clusters	Low risk	No loss of centres reported.
Incorrect analysis	Low risk	Adjusted for clustering at class level by adding random effect.