Schwartz 1980.

Methods	Randomised, placebo‐controlled trial (patients who failed to respond at 1 week crossed over to alternative treatment)
Participants	41 children aged 1.2 to 10 years seen by 2 paediatricians in separate private clinics Effusions present for at least 3 weeks despite previous antibiotics and/or decongestants Diagnosis: 1B, 2C 48% bilateral
Interventions	Antibiotic (sulfisoxazole) plus prednisone 1 mg/kg/day tapering over 7 days (n = 24) versus antibiotic plus placebo (n = 17)
Outcomes	Tympanometry and pneumo‐otoscopy clearing of effusions Follow up at 1 week after entry (data for the period after participants cross‐over have not been included) Not clear whether 'cleared' refers to clearing in all affected ears
Notes	Not clear why numbers in treatment groups unbalanced. Small sample size therefore likely due to chance, but the number of participants enrolled and randomised not stated.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of sequence generation not state
Allocation concealment (selection bias)	Low risk	Quote: "Pulverized prednisone tables or lactose powder packed in unmarked gelatin capsules and placed in identical coded vials by a registered pharmacist"; patients are assumed to have been enrolled in the clinic
Blinding (performance bias and detection bias) All outcomes	Low risk	Unclear if outcome assessors were blind, but study reported as double‐blind
Incomplete outcome data (attrition bias) < 1 month	Unclear risk	41 participants included in study, but not clear if only 41 were randomised
Incomplete outcome data (attrition bias) 1 to 6 months	Unclear risk	—
Selective reporting (reporting bias)	Unclear risk	Poor reporting
Other bias	Unclear risk	Baseline characteristics not reported