Table 4.
Item hierarchy and fit statistics of the PQ-16 under the Rasch Rating Scale Model among pregnant Peruvian women (N=2059)
| Items | Item Difficulty in Logits | Model SE | Infit a |
Outfit a |
||
|---|---|---|---|---|---|---|
| MnSq | Zstd | MnSq | Zstd | |||
| 1. I feel uninterested in the things I used to enjoy. | −1.33 | 0.05 | 1.11 | 5.12 | 1.17 | 5.11 |
| 2. I often seem to live through events exactly as they happened before (de ja vu). | 0.00 | 0.06 | 1.14 | 4.44 | 1.22 | 3.91 |
| 3. I sometimes smell or taste things that other people can’t smell or taste. | −1.71 | 0.05 | 1.08 | 3.59 | 1.14 | 4.00 |
| 4. I often hear unusual sounds like banging, clicking, hissing, clapping or ringing in my ears. | 0.40 | 0.06 | 0.93 | −1.94 | 0.86 | −2.21 |
| 5. I have been confused at times whether something I experienced was real or imaginary. | 0.67 | 0.07 | 0.88 | −2.96 | 0.76 | −3.34 |
| 6. When I look at a person, or look at myself in a mirror, I have seen the face change right before my eyes. | 1.93 | 0.10 | 0.86 | −1.82 | 0.71 | −2.05 |
| 7. I get extremely anxious when meeting people for the first time. | −0.37 | 0.05 | 1.05 | 1.77 | 1.06 | 1.37 |
| 8. I have seen things that other people apparently can’t see. | 1.30 | 0.08 | 0.86 | −2.54 | 0.68 | −3.29 |
| 9. My thoughts are sometimes so strong that I can almost hear them. | 0.50 | 0.06 | 0.86 | −3.80 | 0.70 | −4.63 |
| 10. I sometimes see special meanings in advertisements, shop windows, or in the way things are arranged around me. | −0.26 | 0.05 | 1.11 | 3.89 | 1.09 | 1.93 |
| 11. Sometimes I have felt that I’m not in control of my own ideas or thoughts. | 0.15 | 0.06 | 0.84 | −5.28 | 0.68 | −6.23 |
| 12. Sometimes I feel suddenly distracted by distant sounds that I am not normally aware of | 0.41 | 0.06 | 0.92 | −2.19 | 0.83 | −2.59 |
| 13. I have heard things other people can’t hear like voices of people whispering or talking | 0.70 | 0.07 | 0.86 | −3.43 | 0.73 | −3.80 |
| 14. I often feel that others have it in for me. | 0.13 | 0.06 | 0.90 | −3.32 | 0.78 | −4.16 |
| 15. I have had the sense that some person or force is around me, even though I could not see anyone | −0.49 | 0.05 | 0.97 | −1.19 | 0.93 | −1.90 |
| 16. I feel that parts of my body have changed in some way, or that parts of my body are working differently than before | −2.04 | 0.05 | 1.06 | 2.42 | 1.04 | 1.02 |
| Mean | 0.00 | 0.06 | 0.96 | −0.45 | 0.90 | −1.05 |
| SD | 1.04 | 0.01 | 0.11 | 3.40 | 0.19 | 3.46 |
a
Infit MnSq value and outfit MnSq value should range from 0.6 to 1.4, and from 0.5 to 1.7, respectively. SE, standard error, SD, standard deviation, MnSq, mean square, Zstd, z-standardized.