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Fig. 7 | BMC Medical Research Methodology

Fig. 7

From: Searching for the optimal measuring frequency in longitudinal studies -- an example utilizing short message service (SMS) to collect repeated measures among patients with low back pain

Fig. 7

Relative Risks for experiencing a day with bothersome pain estimated from weekly SMS-answers separating subjects with pain of long duration (>30 days the previous year) from those with short duration (≤30 days the previous year). RR was estimated separately for each week, 1–26, with short duration as the reference category. Dotted vertical lines are shown to help the interpretation of results for measurements up to 8 weeks, 13 weeks and 18 weeks. The trajectories for the two groups are also shown, with short duration as the solid line

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BMC Medical Research Methodology

ISSN: 1471-2288

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