TY - JOUR
T1 - Measurement Invariance of Psychotic-Like Symptoms as Measured With the Prodromal Questionnaire, Brief Version (PQ-B) in Adolescent and Adult Population Samples
AU - Lång, Ulla
AU - Mittal, Vijay Anand
AU - Schiffman, Jason
AU - Therman, Sebastian
N1 - Funding Information:
This work was supported by the National Institute of Mental Health (Grant R01MH112612 to JS) and the Academy of Finland (Grant 317363 to ST, including open access publication fee).
Publisher Copyright:
© Copyright © 2021 Lång, Mittal, Schiffman and Therman.
PY - 2021/1/21
Y1 - 2021/1/21
N2 - Valid measurement of group differences in self-reported psychotic-like experiences (PLEs) requires knowing any group-specific measurement properties of the instruments. We investigated the measurement invariance of the 21-item Prodromal Questionnaire–Brief (PQ-B) questionnaire across gender, ethnic minority/majority status, and presence of depressive symptoms in two different US non-clinical undergraduate samples (N = 1,099). For each item, endorsement of the experience and the associated distress were combined for analysis. A unidimensional model of the PQ-B fit the data well. Across genders, the PQ-B showed configural and metric, but not full scalar invariance; there were statistically significant differences in eight thresholds of six items, most being higher endorsement thresholds for self-identified females. Partial scalar invariance was also found for ethnic status, with five thresholds of three items being higher for the minority participants. For depressive symptomatology, defined as the top quintile by the Beck Depression Inventory–II, partial scalar invariance required dropping one item, after which there were statistically significant differences only in two response thresholds. Overall, a wide range of PLE questionnaire items were found to be robust to gender and ethnicity effects, strengthening confidence in found group differences in PLEs. Although full scalar invariance could not be ascertained for any of the group comparisons, the few found scalar differences across groups were small, with minimal impact on group PLE estimates. However, since PLEs are easily conceptually entangled with depression symptoms, similar items should be considered for exclusion if separable constructs are the target of investigation.
AB - Valid measurement of group differences in self-reported psychotic-like experiences (PLEs) requires knowing any group-specific measurement properties of the instruments. We investigated the measurement invariance of the 21-item Prodromal Questionnaire–Brief (PQ-B) questionnaire across gender, ethnic minority/majority status, and presence of depressive symptoms in two different US non-clinical undergraduate samples (N = 1,099). For each item, endorsement of the experience and the associated distress were combined for analysis. A unidimensional model of the PQ-B fit the data well. Across genders, the PQ-B showed configural and metric, but not full scalar invariance; there were statistically significant differences in eight thresholds of six items, most being higher endorsement thresholds for self-identified females. Partial scalar invariance was also found for ethnic status, with five thresholds of three items being higher for the minority participants. For depressive symptomatology, defined as the top quintile by the Beck Depression Inventory–II, partial scalar invariance required dropping one item, after which there were statistically significant differences only in two response thresholds. Overall, a wide range of PLE questionnaire items were found to be robust to gender and ethnicity effects, strengthening confidence in found group differences in PLEs. Although full scalar invariance could not be ascertained for any of the group comparisons, the few found scalar differences across groups were small, with minimal impact on group PLE estimates. However, since PLEs are easily conceptually entangled with depression symptoms, similar items should be considered for exclusion if separable constructs are the target of investigation.
KW - PQ-B
KW - differential item functioning (DIF)
KW - measurement invariance (MI)
KW - perceptual abnormalities
KW - psychopathology
KW - psychotic experiences
KW - young adults
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U2 - 10.3389/fpsyt.2020.593355
DO - 10.3389/fpsyt.2020.593355
M3 - Article
C2 - 33584365
AN - SCOPUS:85100501162
SN - 1664-0640
VL - 11
JO - Frontiers in Psychiatry
JF - Frontiers in Psychiatry
M1 - 593355
ER -