Allen 2001.

Methods
Participants
Interventions
Outcomes
Notes	See Table 8
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	‘‘Patients were sequentially selected from the patient rosters of two ophthalmic surgeons. [...] On each day data collection surgeons were randomly assigned to have their patients in the experimental or control group.’’ Method of randomisation not stated.
Allocation concealment (selection bias)	High risk	"Office assistants were unaware of the study prepared patient rosters. On each day data collection surgeons were randomly assigned to have their patients in the experimental or control group. Patients were then approached in the waiting room and asked to participate in the study." Patients approached after allocation.
Blinding (performance bias and detection bias) Subjective outcomes	High risk	Not extracted for review (validity of measurement scales unclear).
Blinding (performance bias and detection bias) Objective outcomes	Low risk	Automated measurement of physiological data via Propaq Monitor.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Withdrawals and drop‐outs not described. Physiological outcomes reported for all included patients.
Selective reporting (reporting bias)	Unclear risk	Unknown if selective outcome reporting.
Protection from contamination?	Low risk	Music allocated on an individual basis via headphones.