Table 3.
Test-retest reliability results for questions eliciting numerical responses
| Test | Retest | |||||||
|---|---|---|---|---|---|---|---|---|
| Item number | Item description | Mean (SD) | Mean (SD) | t-value | P value | ICC | 95% CI | SEM |
| Q2 | Mean age of onset of LBP | 13.4 (1.96) | 13.5 (1.93) |
-1.40 | 0.17 | 0.87 | 0.81-0.91 | 1.36 |
| Q6 | Mean intensity for recurrent LBP on VAS | 2.59 (1.27) | 2.63 (1.30) | -1.00 | 0.32 | 0.97 | 0.94-0.98 | 0.44 |
| Q9 | Mean intensity for ‘point’LBP | 2.15 (1.21) |
2.69 (1.31) |
-1.85 | 0.09 | 0.62 | 0.15-0.86 | 1.42 |
Q question, SD standard deviation, ICC Intraclass correlation coefficient, SEM standard error of measurement, CI confidence interval, VAS Visual Analogue Scale, ‘point’=LBP at the point of collecting data