Butz 1990 USA.

Methods	Cluster‐RCT Method of allocation sequence: unclear Allocation concealment: unclear Blinding: none Inclusion of participants in the analysis: unclear Length of follow‐up: 12 months Cluster‐adjustment method: not adjusted
Participants	Number: 24 family day‐care centres, with 108 children (58 intervention, 50 control) Inclusion criteria: not stated Exclusion criteria: unclear Age: 1 month to 7 years
Interventions	Intervention (see Table 5 for detailed description): Large group training (in‐home instruction to day‐care providers) Control: No intervention
Outcomes	Incidence of infectious disease symptoms (diarrhoea)
Notes	Location: Baltimore, Maryland, USA Duration: 12 months
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described.
Allocation concealment (selection bias)	Unclear risk	Not described.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not described.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described.
Incomplete outcome data (attrition bias) All outcomes	Low risk	28 children (114 children were enrolled from the FDCHs but actual number of children used in the analysis is 86).
Selective reporting (reporting bias)	Unclear risk	Did not measure the relative contribution of each component of intervention, however "to reduce reporting bias, all day care providers were aware that the intervention program was being tested in certain homes".
Other bias	Low risk	None observed.