Postal and face-to-face administration of stroke outcome measures: can mixed modes be used?

BACKGROUND AND PURPOSE: Different modes of administration are used to collect stroke outcomes, even within the same study, potentially leading to different results. We investigated the effect of administration mode (postal questionnaire; face-to-face interview) on self-reports of activities of daily living and mood. METHODS: The study was nested within a poststroke motivational interviewing trial. Activities of daily living (Barthel; Nottingham Extended) and mood (General Health Questionnaire; Yale) were collected at 3 and 12 months via postal questionnaire. Participants were approached to respond again via face-to-face interview. Paired t tests (McNemar test) and intraclass correlation coefficients (Cohen κ) were used, with 95% CI, to compare scores (items). RESULTS: Forty-four participants consented. Only Barthel scores were significantly different; they were 1.0 (95% CI, 0.5-1.6) higher face-to-face. The intraclass correlation coefficient for the Barthel was 0.90; for the other scales it was between 0.83 and 0.87. The Yale κ was 0.72. CONCLUSIONS: Modes of administration might be used interchangeably, albeit in conjunction with corrections for the Barthel.