Table 5.

Effect sizes of the primary and secondary outcomes in all study group comparisons according to Cohen’s d^a

Analysis	Effect size (d)
	Rehab vs. Control	Physio vs. Control	Advice vs. Control
Primary outcomes
Physical impairment (PHI)	0.7	0.7	0.4
LBP intensity (VAS)	0.6	0.6	0.4
Quality of Life (QoL)	0.4	0.5	0.2
Sickness absenceb days	0.1	0.0	0.1
Secondary outcomes
Pain related fear - FABQ	0.6	0.4	0.1
Pain related fear - FABQw	0.6	0.5	0.2
Pain related fear - FABQph	0.4	0.1	0.1
Disability - OSW sum	0.8	0.6	0.3
Sickness absenceb periods	0.4	0.0	0.2

^aCohen’s d effect size is interpreted as follows: d < 0.5 small effect size; 0.5 < d < 0.8 medium; 0.8 < d < 1.2 large; d > 1.2 very large effect size. Medium or larger effect sizes are bolded

^bSickness absence = accumulated, all cause sickness absence during two years

FABQ Fear Avoidance Beliefs questionnaire, sum variable, FABQw Fear Avoidance beliefs questionnaire, work subscale, FABQph Fear Avoidance beliefs questionnaire, physical activity subscale, LBP low back pain, QoL health related quality of life, OSW Oswestry Disability scale (sum value)