Issues to consider for judging overall rating of risk of bias		Study methods and comments	Rating of reporting
Definition of the outcome	A clear definition of the LBP outcome is provided, including duration of follow‐up and ICF disability construct; return to work should be clearly defined if it means off work, work re‐integration, work maintenance, or advancement.
Valid and reliable measurement of outcome	The method of outcome measurement used is adequately valid and reliable to limit misclassification bias (e.g. may include relevant outside sources of information on measurement properties, also characteristics, such as blind measurement and confirmation of outcome with valid and reliable test). Valid and reliable LBP outcome measures include: pain intensity, measured by a visual analogue scale (VAS) or other pain scale (e.g. numeric rating scale, or McGill pain score), functional limitations, measured by a LBP‐specific scale (e.g. the Roland‐Morris Disability Questionnaire, or the Oswestry Disability Index). Administrative return to work outcomes are considered valid.
	Clear and appropriate cut‐points for continuous outcome measures (i.e. not data‐dependent) are used.
Method and setting of outcome measurement	The method and setting of outcome measurement is the same for all study participants.