Research Article
Evaluating the Longitudinal Item and Category Stability of the SF-36 Full and Summary Scales Using Rasch Analysis
Table 1
SF-36 total scale Rasch analysis item statistics for six waves of data collection.
| ā | Wave 1 | Wave 2 | Wave 3 | Wave 4 | Wave 5 | Wave 6 | SF36 ITEM | LOGIT MEASURE | MODEL S.E | PTMEA CORR | LOGIT MEASURE | MODEL S.E. | PTMEA CORR | LOGIT MEASURE | MODEL S.E. | PTMEA CORR | LOGIT MEASURE | MODEL S.E. | PTMEA CORR | LOGIT MEASURE | MODEL S.E. | PTMEA CORR | LOGIT MEASURE | MODEL S.E. | PTMEA CORR |
| 1: Q1 | -0.36 | 0.01 | -0.16 | -0.37 | 0.01 | -0.14 | -0.37 | 0.01 | -0.09 | -0.52 | 0.01 | -0.06 | -0.60 | 0.01 | -0.05 | -0.68 | 0.01 | 0.01 | 2: Q2 | -0.39 | 0.01 | 0.04 | -0.44 | 0.01 | 0.03 | -0.51 | 0.01 | 0.03 | -0.56 | 0.01 | 0.08 | -0.66 | 0.01 | 0.06 | -0.73 | 0.01 | 0.11 | 3: Q3A | 1.94 | 0.02 | 0.24 | 1.96 | 0.02 | 0.26 | 2.05 | 0.02 | 0.29 | 2.08 | 0.02 | 0.30 | 2.09 | 0.03 | 0.29 | 2.31 | 0.04 | 0.27 | 4: Q3B | 0.36 | 0.01 | 0.46 | 0.39 | 0.01 | 0.44 | 0.53 | 0.01 | 0.44 | 0.67 | 0.01 | 0.45 | 0.77 | 0.02 | 0.45 | 0.95 | 0.02 | 0.41 | 5: Q3C | 0.30 | 0.01 | 0.47 | 0.32 | 0.01 | 0.46 | 0.34 | 0.01 | 0.44 | 0.44 | 0.01 | 0.46 | 0.49 | 0.02 | 0.44 | 0.57 | 0.02 | 0.41 | 6: Q3D | 0.82 | 0.01 | 0.45 | 0.84 | 0.01 | 0.44 | 0.93 | 0.01 | 0.46 | 1.00 | 0.02 | 0.47 | 1.11 | 0.02 | 0.46 | 1.25 | 0.02 | 0.44 | 7: Q3E | 0.13 | 0.01 | 0.51 | 0.15 | 0.01 | 0.50 | 0.24 | 0.01 | 0.50 | 0.28 | 0.01 | 0.49 | 0.36 | 0.02 | 0.49 | 0.46 | 0.02 | 0.47 | 8: Q3F | 0.54 | 0.01 | 0.44 | 0.63 | 0.01 | 0.41 | 0.72 | 0.01 | 0.41 | 0.73 | 0.02 | 0.43 | 0.73 | 0.02 | 0.43 | 0.81 | 0.02 | 0.40 | 9: Q3G | 0.44 | 0.01 | 0.49 | 0.53 | 0.01 | 0.46 | 0.73 | 0.01 | 0.46 | 0.87 | 0.02 | 0.47 | 1.05 | 0.02 | 0.44 | 1.24 | 0.02 | 0.44 | 10: Q3H | 0.05 | 0.01 | 0.52 | 0.10 | 0.01 | 0.49 | 0.23 | 0.01 | 0.49 | 0.36 | 0.01 | 0.50 | 0.48 | 0.02 | 0.48 | 0.65 | 0.02 | 0.48 | 11: Q3I | -0.14 | 0.01 | 0.48 | -0.13 | 0.01 | 0.45 | -0.07 | 0.01 | 0.46 | -0.02 | 0.01 | 0.44 | 0.05 | 0.01 | 0.44 | 0.11 | 0.02 | 0.45 | 12: Q3J | -0.28 | 0.01 | 0.36 | -0.31 | 0.01 | 0.35 | -0.29 | 0.01 | 0.32 | -0.24 | 0.01 | 0.32 | -0.23 | 0.01 | 0.32 | -0.23 | 0.02 | 0.32 | 13: Q4A | 1.26 | 0.01 | 0.35 | 1.31 | 0.01 | 0.33 | 1.41 | 0.02 | 0.29 | 1.41 | 0.02 | 0.28 | 1.46 | 0.02 | 0.26 | 1.47 | 0.03 | 0.27 | 14: Q4B | 1.63 | 0.01 | 0.35 | 1.74 | 0.02 | 0.32 | 1.87 | 0.02 | 0.29 | 1.89 | 0.02 | 0.28 | 1.92 | 0.03 | 0.27 | 1.94 | 0.03 | 0.26 | 15: Q4C | 1.47 | 0.01 | 0.36 | 1.53 | 0.02 | 0.36 | 1.60 | 0.02 | 0.31 | 1.69 | 0.02 | 0.30 | 1.74 | 0.02 | 0.28 | 1.78 | 0.03 | 0.24 | 16: Q4D | 1.50 | 0.01 | 0.36 | 1.58 | 0.02 | 0.35 | 1.67 | 0.02 | 0.31 | 1.73 | 0.02 | 0.30 | 1.77 | 0.02 | 0.28 | 1.80 | 0.03 | 0.28 | 17: Q5A | 1.02 | 0.01 | 0.37 | 1.01 | 0.01 | 0.35 | 1.00 | 0.01 | 0.31 | 0.96 | 0.02 | 0.30 | 0.92 | 0.02 | 0.30 | 0.89 | 0.02 | 0.27 | 18: Q5B | 1.22 | 0.01 | 0.36 | 1.22 | 0.01 | 0.35 | 1.23 | 0.02 | 0.31 | 1.21 | 0.02 | 0.30 | 1.18 | 0.02 | 0.29 | 1.15 | 0.02 | 0.27 | 19: Q5C | 1.05 | 0.01 | 0.35 | 1.03 | 0.01 | 0.33 | 1.01 | 0.01 | 0.31 | 0.99 | 0.02 | 0.29 | 0.95 | 0.02 | 0.29 | 0.91 | 0.02 | 0.26 | 20: Q6 | 1.17 | 0.01 | -0.22 | 1.35 | 0.01 | -0.20 | 0.93 | 0.01 | -0.16 | 0.69 | 0.01 | -0.16 | 0.48 | 0.02 | -0.12 | 0.37 | 0.02 | -0.08 | 21: Q7 | -0.28 | 0.01 | -0.06 | -0.26 | 0.01 | -0.04 | -0.40 | 0.01 | 0.01 | -0.50 | 0.01 | 0.01 | -0.57 | 0.01 | 0.03 | -0.67 | 0.01 | 0.07 | 22: Q8 | 0.68 | 0.01 | -0.18 | 0.73 | 0.01 | -0.14 | 0.44 | 0.01 | -0.11 | 0.26 | 0.01 | -0.09 | 0.12 | 0.01 | -0.04 | -0.01 | 0.02 | -0.02 | 23: Q9A | -0.59 | 0.01 | -0.05 | -0.67 | 0.01 | -0.06 | -0.79 | 0.01 | 0.00 | -0.82 | 0.01 | -0.02 | -0.93 | 0.01 | 0.01 | -1.06 | 0.01 | 0.05 | 24: Q9B | -2.04 | 0.01 | 0.39 | -2.30 | 0.01 | 0.36 | -2.39 | 0.01 | 0.33 | -2.40 | 0.01 | 0.31 | -2.38 | 0.02 | 0.31 | -2.42 | 0.02 | 0.27 | 25: Q9C | -2.64 | 0.01 | 0.40 | -2.92 | 0.02 | 0.35 | -2.98 | 0.02 | 0.34 | -3.01 | 0.02 | 0.30 | -2.86 | 0.02 | 0.31 | -2.89 | 0.02 | 0.27 | 26: Q9D | -0.30 | 0.01 | 0.06 | -0.20 | 0.01 | 0.01 | -0.28 | 0.01 | 0.09 | -0.29 | 0.01 | 0.07 | -0.30 | 0.01 | 0.08 | -0.37 | 0.01 | 0.12 | 27: Q9E | -0.77 | 0.01 | -0.05 | -0.89 | 0.01 | -0.09 | -1.00 | 0.01 | -0.04 | -1.06 | 0.01 | -0.05 | -1.17 | 0.01 | -0.02 | -1.35 | 0.01 | 0.00 | 28: Q9F | -2.01 | 0.01 | 0.40 | -2.15 | 0.01 | 0.34 | -2.15 | 0.01 | 0.35 | -2.16 | 0.01 | 0.34 | -2.13 | 0.02 | 0.33 | -2.13 | 0.02 | 0.31 | 29: Q9G | -1.63 | 0.01 | 0.44 | -1.70 | 0.01 | 0.41 | -1.67 | 0.01 | 0.40 | -1.60 | 0.01 | 0.40 | -1.56 | 0.01 | 0.40 | -1.57 | 0.01 | 0.37 | 30: Q9H | 0.24 | 0.01 | 0.14 | 0.33 | 0.01 | 0.09 | 0.26 | 0.01 | 0.13 | 0.23 | 0.01 | 0.14 | 0.14 | 0.01 | 0.12 | 0.08 | 0.02 | 0.15 | 31: Q9I | -1.23 | 0.01 | 0.39 | -1.22 | 0.01 | 0.37 | -1.15 | 0.01 | 0.34 | -1.07 | 0.01 | 0.36 | -1.03 | 0.01 | 0.34 | -1.04 | 0.01 | 0.31 | 32: Q10 | -1.34 | 0.01 | 0.35 | -1.39 | 0.01 | 0.31 | -1.30 | 0.01 | 0.28 | -1.23 | 0.01 | 0.26 | -1.20 | 0.01 | 0.24 | -1.18 | 0.01 | 0.24 | 33: Q11A | -1.39 | 0.01 | 0.33 | -1.48 | 0.01 | 0.31 | -1.49 | 0.01 | 0.28 | -1.50 | 0.01 | 0.25 | -1.49 | 0.01 | 0.26 | -1.52 | 0.01 | 0.20 | 34: Q11B | 0.28 | 0.01 | 0.03 | 0.43 | 0.01 | -0.01 | 0.32 | 0.01 | 0.08 | 0.25 | 0.01 | 0.07 | 0.10 | 0.01 | 0.10 | -0.01 | 0.02 | 0.14 | 35: Q11C | -0.68 | 0.01 | 0.29 | -0.75 | 0.01 | 0.27 | -0.65 | 0.01 | 0.29 | -0.59 | 0.01 | 0.25 | -0.50 | 0.01 | 0.25 | -0.48 | 0.01 | 0.24 | 36: Q11D | -0.02 | 0.01 | -0.06 | 0.01 | 0.01 | -0.09 | -0.03 | 0.01 | 0.00 | -0.17 | 0.01 | -0.01 | -0.31 | 0.01 | 0.04 | -0.40 | 0.01 | 0.09 |
|
|
Note. MODEL S.E. = model standard error; PTMEA CORR = point measure correlation.
|