Skip to main content

Table 2 Power of trial to detect differences across main comparisons

From: UK Back pain Exercise And Manipulation (UK BEAM) trial – national randomised trial of physical treatments for back pain in primary care: objectives, design and interventions [ISRCTN32683578]

Power to detect difference of 2.5 RMDQ points at 1% significance level No interaction present between manipulation and exercise Interaction present between manipulation and exercise Analysing only completersa (no interactions present)
Exercise vs. AM only >99% >99% >99%
Manipulation vs. AM only >99% >99% >99%
Site of manipulationb 80% 42% 64%
Site of manipulationc 91% 66% 83%
  1. a Based on estimated completion rate of 75% b Power to detect difference of 1.67 RDQ points at 1% significance level c Power to detect difference of 1.67 RDQ points at 5% significance level