| Date |
| ||||
| before OP (n = 458) | after OP (n = 458) | Difference | |||
Variable | mean | s.d. | mean | s.d. | mean | s.d. |
Pron | 15.15 | 11.87 | 1.24 | 2.81 | 13.91 | 11.65 |