O'Connor 1992.

Methods	Setting: UK, hospital outpatient clinic Randomisation: yes, computer‐generated randomisation sequence Allocation concealment: yes Design: crossover, 4 week washout Intervention period: 2 weeks Masking: double blind Excluded: not stated Withdrawals: stated (none) Baseline characteristics: comparable FEV1 (% predicted) Jadad score=4
Participants	12 adults: 6M 6F Age range: 20 to 46 years Inclusion criteria: Non smoking adult patients with mild asthma Positive allergen skin prick test to a common airborne allergen (Dermatophagoides pteronyssinus, mixed grass pollen, cat or dog fur) FEV1 (% predicted) > 80 Exclusion criteria: Exacerbation of asthma or respiratory infection in previous 6 weeks
Interventions	BUD: 400 mcg 2pfs 2xdaily (1600 mcg/d) Placebo: 2 pfs 2xdaily Delivery device: Turbuhaler DPI
Outcomes	FEV1 Methacholine BHR (PC20 FEV1) Sodium metabisulphite BHR (PC20 FEV1) Adenosine monophosphate BHR (PC20 FEV1) Blood eosinophil count
Notes	Reply from author clarifying method of random order generation and confirming use of allocation concealment.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Low risk	A ‐ Adequate