Table 2 Differences between the two data-obtaining methods
Differences across time in proportions of agreement in the two different data capture methods | |||
|---|---|---|---|
| Â | Week compared to month comparing SMS-T-Q to telephone interview | Week compared to year comparing SMS-T-Q to telephone interview | Month compared to year comparing SMS-T-Q to telephone interview |
Q1: How many days have you had problems due to LBP? | 22/25 compared to 19/25: Difference is 12% (95% CI: -9:33), p = .27 | 22/25 compared to 10/25: Difference is 48% (95% CI: 25:71), p = .000 | 19/25 compared to 10/25: Difference is 36% (95% CI:11:61), p = .01 |
Q2: How many days have you been on sick leave due to the LBP problems? | 24/24 compared to 22/25: Difference is 12% (95% CI: -0,7:25), p = .08 | 24/24 compared to 12/25: Difference is 52% (95% CI:32:72), p = .000 | 22/25 compared to 12/25: Difference is 40% (95% CI: 17:63), p = 0.002 |
Bland-Altman average difference between measurements with 95% limits of agreement | |||
| Â | 1 week recall | 1 month recall | 1 year recall |
Q1: Average difference between the two different data capture methods | 0.1 days (-1 day: 0.9 day) | 0.7 days (-4 days: 5 days) | 36 days (-175 days: 103 days) |
Q2: Average difference between the two data capture methods | 0.0 days | 0.3 days (-3 days: 2.5 days) | 26 days (-67 days: 119 days) |