Table 1 Analysis by the Rasch model - overall fit statistics for J-EAT-10
Scale analysis | % Extr. | Fit residuals mean (SD) | Item-trait interaction | Reliability | Unidi-mensionality | |||
|---|---|---|---|---|---|---|---|---|
Item | Person | χ2 (df) | P | PSI / α | Power of fit | T-test % | ||
Initial analyses | ||||||||
 1. Full sample (N = 1144) | 42% | −0.66 (4.16) | − 0.30 (1.08) | 485.48 (40) | < 0.001 | 0.65 / 0.85 | Good | 2.27% |
 2. Independent group (N = 594) | 53% | − 0.82 (2.13) | −0.37 (0.86) | 175.92 (30) | < 0.001 | 0.32 / 0.72 | Too low | 0.72% |
 3. Dependent group (N = 550) | 30% | −0.19 (3.53) | −0.25 (1.17) | 293.28 (40) | < 0.001 | 0.74 / 0.87 | Good | 1.83% |
Analysis after reducing to three scoring categories (full sample,N = 1144) | ||||||||
 4. Scoring structure: 00122a | 65% | −0.89 (3.21) | −0.25 (0.77) | 284.01 (40) | < 0.001 | 0.38 / 0.76 | Low | 1.73% |
 5. Scoring structure: 01112 | 42% | −1.73 (4.72) | −0.35 (0.90) | 416.01 (40) | < 0.001 | 0.69 / 0.83 | Good | 1.21% |
 6. Scoring structure: 01122 | 42% | −1.90 (4.34) | −0.38 (1.01) | 448.90 (40) | < 0.001 | 0.66 / 0.83 | Good | 2.27% |
 7. Scoring structure: 01222 | 43% | −0.78 (4.26) | −0.26 (1.11) | 439.37 (40) | < 0.001 | 0.65 / 0.89 | Reasonable | 0.76% |
 8. Scoring structure: 00112 | 65% | −0.56 (4.04) | −0.24 (0.74) | 225.24 (30) | < 0.001 | 0.49 / 0.76 | Low | 1.98% |
Optimal values <  15% | 0 (<  1.00) | 0 (<  1.00) |  | > 0.05 | > 0.70 | < 5% | ||