Research Article
Development of the 8-Item Phlegm Pattern Questionnaire (PPQ-8) Using Rasch Analysis
Table 2
Category characteristics of the 7- and 6-point Likert scales.
| | Scale | Category (response) | Observed count (%) | Average measure | Expected measure | Infit MnSq | Outfit MnSq | Step calibration | Category measure |
| | 7-point Likert | 1 (disagree very strongly) | 829 (11) | −1.39 | −1.24 | 0.86 | 0.93 | None | −3.06 | | 2 (disagree strongly) | 2276 (31) | −0.57 | −0.63 | 0.99 | 0.94 | −1.89 | −1.21 | | 3 (disagree) | 873 (12) | −0.34 | −0.37 | 0.96 | 1.06 | 0.47 | −0.44 | | 4 (neither disagree nor agree) | 1290 (18) | −0.15 | −0.16 | 0.97 | 1.20 | −0.65 | 0.03 | | 5 (agree) | 1093 (15) | 0.01 | 0.03 | 1.06 | 1.24 | 0.10 | 0.52 | | 6 (agree strongly) | 677 (9) | 0.16 | 0.22 | 1.13 | 1.27 | 0.60 | 1.29 | | 7 (agree very strongly) | 237 (3) | 0.46 | 0.42 | 1.01 | 1.26 | 1.37 | 2.74 |
| | 6-point Likert | 1 (disagree very strongly) | 829 (11) | −1.78 | −1.65 | 0.91 | 0.93 | None | −3.37 | | 2 (disagree strongly) | 2276 (31) | −0.72 | −0.77 | 0.94 | 0.89 | −2.14 | −1.46 | | 3 (disagree) | 2163 (30) | −0.31 | −0.34 | 0.97 | 1.10 | −0.49 | −0.23 | | 4 (agree) | 1093 (15) | −0.02 | −0.01 | 1.02 | 1.12 | 0.51 | 0.56 | | 5 (agree strongly) | 677 (9) | 0.22 | 0.30 | 1.11 | 1.22 | 0.62 | 1.41 | | 6 (agree very strongly) | 237 (3) | 0.61 | 0.61 | 1.04 | 1.24 | 1.50 | 2.85 |
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Disordering response category, where the step calibration value became lower than that of the previous category. |
