Analysis of the schizotypal ambivalence scale

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Lauren B.F. Deters (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
John Willse

Abstract: The purpose of this study was threefold: a) to provide a thorough modern measurement example in a field where it is more limited in use, b) to investigate the psychometric properties of the Schizotypal Ambivalence Scale (SAS) through IRT measurement models, and c) to use the evaluation of the psychometric properties of the SAS to identify evidence for adherence to the relevant guidelines outlined in the Standards for Educational and Psychological Testing (hereafter Standards; AERA, APA, & NCME, 2014). Together, these goals were to contribute to the argument that the SAS is a robust measure of the ambivalence construct. An archived sample of over 7,000 undergraduate students was used to conduct all analyses. Comparison of eigenvalue ratios indicated that the SAS data could be interpreted as essential unidimensional; however, results from the DIMTEST procedure (Stout, 2006) suggested a departure from unidimensionality. Results from the analysis provided adequate evidence for Standard 1.13 (AERA, APA, & NCME, 2014). The data were modeled via 1PL, 2PL, and 3PL models, and the 2PL model best fit the data. Examination of item-level statistics indicated that items 4, 8, 10, and 15 were endorsed more frequently than other items, and that items 2, 3, 9, 14, and 19 were the most discriminating. Items 7, 15, and 18 were flagged for possible misfit. Results from the analysis of local independence revealed that many item pairs, particularly items 10 through 16, may have violated the assumption of local independence. Furthermore, results from DIMTEST (Stout, 2006) were significant, and the partitioning of items indicated that items 12, 13, 14, and 16 were dimensionally similar. Analysis of the item-level characteristics provided evidence for Standard 4.10 (AERA, APA, & NCME, 2014). Analysis of information provided by the SAS at the item level revealed that items 2, 3, 9, 14, and 19 provided the most information at the higher end of the theta (?) scale. Analysis of information at the scale level indicated that the reliability was a = .84, and that the highest point on the TIF occurred at ? = 0.8. The TIF and Cronbach’s a provided evidence for Standards 2.0 and 2.3, and documentation of evidence for Standard 7.12 (AERA, APA, & NCME, 2014). Analysis of DIF revealed that only item 4 exhibited moderate DIF. In general, these results indicated that the SAS can be used across populations without concerns of items performing differently across subgroups. These results provided evidence for Standard 4.10, Standard 3.0, and Standard 3.1 (AERA, APA, & NCME, 2014).

Additional Information

Language: English
Date: 2017
Model utility, Psychometric, Schizotypal, Schizotypy, Validity
Schizotypal personality disorder $x Diagnosis
Schizophrenia $x Diagnosis

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