Table 2. Risk of bias of the included clinical effectiveness studies of chiropractic care for non-specific low back pain.

	Random sequence generation	Allocation concealment	Blinding of participants	Blinding of personnel /care providers	Blinding of outcomes assessors	Incomplete outcome data	Selective outcome reporting	Group similarity at baseline	Co-interventions	Compliance	Intention-to-treat-analysis	Timing of outcome assessments	Other bias	Overall risk of bias
Bronfort 2011[50]	Low	Low	High	High	High	Low	Low	Low	Low	Low	Low	Low	Low	Low
Cherkin 1998 [51]	Unclear	Low	High	High	High	Low	Low	Low	Low	Unclear	Low	Low	Low	Low
Herzog 1991 [52]	Unclear	Unclear	High	High	High	High	Unclear	High	Low	Unclear	High	High	High	High
Hurwitz 2002 [45, 46]	Low	Low	High	High	High	Low	Low	Low	High	Low	Low	Low	Low	Low
Meade 1990 [43, 44]	Low	Unclear	High	High	High	Low	Low	Low	Unclear	Unclear	Low	Low	High	Low
Petersen 2011[53]	Low	Low	High	High	High	Low	High	Low	Low	High	Low	Low	Low	Low