Table 2 Frequencies (%) of responses to the SF-12 mental health (MH) and physical health (PH) sub-scale items
From: Differential item functioning of the SF-12 in a population-based regional joint replacement registry
MH Sub-scale | |||||
| Â | All of the time | Most of the time | Some of the time | A little of the time | None of the time |
 M1: Accomplished less than would like | 634 (7.2) | 1324 (15.0) | 2108 (23.9) | 1858 (21.1) | 2896 (32.8) |
 M2: Less careful than usual | 564 (6.4) | 1240 (14.1) | 1998 (22.7) | 1841 (20.9) | 3177 (36.0) |
 M3: Felt calm and peaceful | 373 (4.2) | 1227 (13.9) | 2510 (28.5) | 4094 (46.4) | 616 (7.0) |
 M4: Have a lot of energy | 1017 (11.5) | 2401 (27.2) | 3150 (35.7) | 2027 (23.0) | 225 (2.6) |
 M5: Felt downhearted and depressed | 165 (1.9) | 595 (6.7) | 2254 (25.6) | 2860 (32.4) | 2946 (33.4) |
| Â | Not at all | A little bit | Moderately | Quite a bit | Extremely |
 M6: Have social limitations | 556 (6.3) | 1352 (15.3) | 2545 (28.9) | 1915 (21.7) | 2452 (27.8) |
PH Sub-scale | |||||
| Â | Excellent | Very good | Good | Fair | Poor |
 P1: General health | 150 (1.7) | 1021 (11.6) | 4181 (47.4) | 2892 (32.8) | 576 (6.5) |
| Â | Yes, limited a lot | Yes, limited a little | No, not limited at all | Â | Â |
 P2: Limits in moderate activity | 5198 (58.9) | 3031 (34.4) | 591 (6.7) |  |  |
 P3: Climbing several flights of stairs | 6563 (74.4) | 1910 (21.7) | 347 (3.9) |  |  |
| Â | All of the time | Most of the time | Some of the time | A little of the time | None of the time |
 P4: Accomplished less than would like | 2564 (29.1) | 3199 (36.3) | 2049 (23.2) | 731 (8.3) | 277 (3.1) |
 P5: Limited in work and activity | 2680 (30.4) | 3291 (37.3) | 1989 (22.6) | 633 (7.2) | 227 (2.6) |
 P6: Have pain with normal work | 1825 (20.7) | 3942 (44.7) | 2118 (24.0) | 804 (9.1) | 131 (1.5) |