OBJECTIVES: Electronic methods (ePRO, E) are increasingly being used for patient diaries and questionnaires. Where paper (P) instruments are migrated to E it is necessary to compare to the original to to determine if the different modalities are equivalent. We have carried out an equivalence study of a number of instruments including the EQ-5D in rheumatoid arthritis. METHODS: A total of 43 patients (31 female) aged 32 - 83 years took part in a single session during which they completed P and E (Palm TX handheld) assessments in randomised order, with a 45 minute interval between the two modes. Assessments included measures of pain, fatigue, disability and health status. RESULTS: Mean scores were similar between the two modes. Utility P: 0.612; E: 0.608; Effect size of P-E difference: -0.017. ICC=0.79. VAS P: 64.2; E: 64.5; Effect size: 0.013; ICC = 0.75. All patients found both P and E either very easy or quite easy to use. CONCLUSIONS: The low magnitude of the effect sizes does not suggest that any significant differences are occurring between modes. ICC values met the a priori threshold of 0.75 for "excellent" agreement, and were in general agreement with paper retest reliability for this scale.This study supports the equivalence of an electronic method of completing the EQ-5D instrument compared to the original paper version.