Leeuw 2008.

Methods	RCT; 2 arms; assessed at 2 pre‐treatment occasions, post‐treatment, 6‐month follow‐up, 12‐month follow‐up
Participants	End of treatment n = 77 Start of treatment n = 85 Sex: 41 F, 44 M Mean age = 45.3 (SD 9.5) Source = rehabilitation clinics, occupational health, pain department Diagnosis = back pain (and at least moderate fear on TSK) Mean years of pain = 9
Interventions	"Exposure in vivo" "Operant graded activity"
Outcomes	Primary pain outcome: MPQ pain intensity Primary disability outcome: Quebec Back Pain Disability Scale (Dutch version) Primary mood outcome: none Catastrophising outcome: PCS 1. Quebec Back Pain Disability Scale (Dutch version) 2. Patient Specific Complaints: VAS 0 to 100 of difficulty with 3 activities 3. Perceived harmfulness of activities (PHODA) 4. Pain Catastrophizing Scale: catastrophising 5. Daily activity: actimeter 6. Pain: mean of VAS 0 to 100 scales for current, worst and least pain
Notes	December 2009 search Exposure in vivo versus operant graded activity: analyses 5.1, 5.2, 5.4, 6.1, 6.2, 6.4 Yates quality scale: total quality = 32/35, design quality = 24/26, treatment quality = 8/9
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“predetermined and computer‐generated randomization schedule”
Allocation concealment (selection bias)	Low risk	Sealed envelope; research assistant only could access randomization schedule
Incomplete outcome data (attrition bias) All outcomes	Low risk	Fully reported
Selective reporting (reporting bias)	Low risk	Fully reported
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Electronic administration of assessments