Reliability
CM
Test–retest reliability results, estimated in stable patients treated with placebo, showed moderate correlations for WPAI presenteeism (ICC: all patients = 0.438; EM patients = 0.227; CM patients = 0.893) and WPAI non-work-related Activity Impairment (ICC: all patients = 0.446; EM patients = 0.272; CM patients = 0.653) and a fair correlation for WPAI overall work productivity loss (ICC: all patients = 0.360; EM patients = 0.158; CM patients = 0.885) [