Chao 2008.

Study characteristics
Methods	Randomised controlled trial for 12 months
Participants	232 children with AOM presenting to 1 paediatric emergency department in an urban public hospital in the Bronx, New York, USA. Data were obtained from 206 participants, of whom 100 were randomised to no antibiotics and 106 were randomised to delayed antibiotic prescription. Age: median age in the no antibiotic group was 5.0 years (IQR 3.7 to 6.7) and in the delayed antibiotic group was 3.7 years (IQR 2.8 to 5.8) Sex:no antibiotic group: 47 males, 53 females; delayed antibiotic group: 60 males, 46 females Exclusion criteria: children were excluded if they had a history of immunodeficiency, craniofacial abnormalities, were already taking antibiotics, had concurrent bacterial infection requiring antibiotic treatment, no telephone contact, AOM in last 30 days, pain did not settle with analgesia after 30 minutes, or 48 hours of otalgia and fever
Interventions	No antibiotics (observation) versus delayed antibiotics. Participants in the delayed antibiotic group were given a script, which they were instructed to fill if needed.
Outcomes	Primary outcomes: data on fever, pain, antibiotic use and patient satisfaction were collected by a research assistant during a phone call 7 to 10 days after the initial presentation Secondary outcomes: adverse events were collected by a research assistant during a phone call 7 to 10 days after the initial presentation
Notes	The funding source for this study was not described
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random number table
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Outcome assessor blinded. Study authors did not indicate if participant and care provider were blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Missing data were described and ITT analysis applied. 232 participants were correctly enrolled, and 206 completed the final interview.
Selective reporting (reporting bias)	Low risk	Prespecified outcomes were reported
Other bias	Unclear risk	Funding not described