Rempel 2007.

Methods	RCT; no info on randomisation procedure
Participants	Chronic neck and shoulder pain in sewing machine operators; n = 277. Performed sewing machine work for more than 20 hours per week
Interventions	Chair with flat seat: n = 72 Chair with curved seat: n = 100 Control: n = 105 Miscellaneous items provided to all participants were a footrest, a small table‐top storage box for items such as scissors, a side table, a task lamp and reading glasses   Four months of follow‐up
Outcomes	Pain, job content (job content questionnaire)
Notes	No data available
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details of randomisation method
Allocation concealment (selection bias)	Unclear risk	No details on treatment allocation
Blinding of participants?	High risk	Participant not blinded
Blinding of caregivers?	Unclear risk	Unclear whether caregiver was blinded
Blinding of outcome assessment (detection bias) All outcomes	High risk	Participant‐reported outcomes and participant not blinded
Incomplete outcome data (attrition bias) All outcomes ‐ <20% drop‐outs?	High risk	209/277 completed the study (25% dropout rate)
Incomplete outcome data (attrition bias) All outcomes ‐ ITT analysis performed?	High risk	No ITT analysis
Selective reporting (reporting bias)	Unclear risk	No protocol
Similarity of baseline characteristics?	Unclear risk	Comparison of baseline outcome measures not given
Co‐interventions avoided?	Unclear risk	Unclear whether co‐interventions were avoided
Compliance acceptable ?	Unclear risk	Unclear compliance
Timing outcome assessment comparable?	Low risk	Timing was comparable