Giles 1996.

Study characteristics
Methods	RCT. Cross‐over design (2‐week washout period). Location: single centre in USA. Duration: 4 weeks of treatment followed by 2‐week washout and then 4 weeks of alternative treatment; follow‐up not stated.
Participants	14 participants. Age and sex of the participants was unspecified, but as parents were also questioned it would suggest they were concerned with a paediatric population.
Interventions	PD&P versus flutter. 2x daily for 15 min each treatment.
Outcomes	Participant preference, wet and dry sputum weight, FVC and FEV1 were measured pre‐study baseline and at the end of each treatment period. Sputum collected on the last treatment of each treatment period.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not discussed.
Allocation concealment (selection bias)	Unclear risk	Not discussed.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not discussed.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not discussed.
Selective reporting (reporting bias)	High risk	Parents were also questioned therefore it may be reasonable to assume that they may have influenced the children's decision as to preference.
Other bias	Unclear risk	Abstract only.