Table 4.
Rasch reliability and fit statistics for the full PTMQ, the two subgroups identified from multidimensionality assessment of the PTMQ, and each of the six individual subdomains in the PTMQ survey
| PTMQ Subgroups | PTMQ Subdomains | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Parameters | Rasch Model Expectations | PTMQ | Altruisticb | Careerc | Intrinsic | Identified | Introjected | Career | External | Amotivation | ||
| Misfitting Items | Fit residual ± 2.5 logits[a] [19] | None | - | - | None | None | None | None | None | None | ||
| Targeting | Item Location (logits) | Difference in person and item means < 1 [36] | 0.00 ± 1.05 | 0.00 ± 1.21 | 0.00 ± 0.94 | 0.00 ± 1.06 | 0.00 ± 1.54 | 0.00 ± 1.93 | 0.00 ± 0.77 | 0.00 ± 1.60 | 0.00 ± 1.53 | |
| Person Location (logits) | -1.46 ± 0.81 | -2.57 ± 1.35 | -1.07 ± 1.22 | -3.17 ± 2.11 | -5.47 ± 2.17 | -2.34 ± 2.64 | -0.50 ± 1.56 | -2.79 ± 2.40 | -2.60 ± 1.97 | |||
| Item-trait Chi-square Interaction | χ2 | - | 80.45 | 67.41 | 35.59 | 12.48 | 3.94 | 2.46 | 8.49 | 3.13 | 7.44 | |
| df | - | 36 | 20 | 16 | 8 | 6 | 4 | 6 | 6 | 6 | ||
| p | p > 0.05a | < 0.0001 | < 0.0001 | 0.003 | 0.13 | 0.69 | 0.65 | 0.19 | 0.79 | 0.28 | ||
| PSI | > 0.7 [37] | 0.82 | 0.78 | 0.83 | 0.74 | 0.57 | 0.72 | 0.72 | 0.68 | 0.61 | ||
| Item fit residual (logits) | 0 ± 1 [19] | 0.23 ± 1.26 | 0.02 ± 2.23 | 0.20 ± 1.28 | -0.15 ± 1.10 | 0.37 ± 0.51 | 0.24 ± 0.38 | 0.21 ± 0.71 | 0.23 ± 0.23 | 0.18 ± 0.57 | ||
| Person fit residual (logits) | 0 ± 1 [19] | -0.20 ± 1.26 | -0.18 ± 0.97 | -0.25 ± 1.11 | -0.40 ± 0.85 | -0.20 ± 0.61 | -0.34 ± 0.53 | -0.40 ± 0.95 | -0.23 ± 0.71 | -0.36 ± 0.97 | ||
| PCA (Eigenvalue for 1st Contrast) | < 2.5 [2] [36] | 4.93 | 2.31 | 2.53 | 1.84 | 1.64 | 1.95 | 1.66 | 1.60 | 1.95 | ||
| Variance by the first factor | > 50% [36] | 27.40% | 23.10% | 31.70% | 45.97% | 57.75% | 97.31% | 55.30% | 53.32% | 64.93% | ||
| Differential Item Functioning (DIF) | Course | - | - | - | - | None | None | None | None | None | None | |
| Sex | - | - | - | - | None | None | None | None | Item 15 (F = 8.16, p = 0.0054) | None | ||
| Teaching Years | - | - | - | - | None | None | None | None | None | None | ||
a. Non-significant Chi-square values using a Bonferroni correction at the p = 0.01 level
b. Intrinsic, Identified, and Amotivation subdomains based on individual item loadings on PC1 from the PTMQ analysis
c. Introjected, Career, and External subdomains based on individual item loadings on PC1 from the PTMQ analysis