Examining the psychometric properties of the WISC-IV in low and normal IQ samples

Çelik S., Eroğlu-Ada F., Sözer Boz E.

BMC Psychology, vol.14, no.1, 2026 (SSCI, Scopus) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 1
  • Publication Date: 2026
  • Doi Number: 10.1186/s40359-025-03927-y
  • Journal Name: BMC Psychology
  • Journal Indexes: Social Sciences Citation Index (SSCI), Scopus, IBZ Online, MEDLINE, Psycinfo, Directory of Open Access Journals
  • Keywords: Factor structure, Intellectual disabilities, Low and normal IQ groups, Measurement invariance, SLODR effect, WISC-IV
  • Çanakkale Onsekiz Mart University Affiliated: Yes

Abstract

Background: The Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) is one of the leading instruments in general ability assessments; however, findings regarding its factor structure are still controversial. Methods: In this study, the single-factor, correlated four-factor, higher-order factor, and bifactor models for the 10 basic tests of the WISC-IV were examined on systematically controlled samples with low (IQ ≤ 79; N = 141) and normal scores (IQ > 80; N = 222). Results: Our research findings revealed that only the bifactor and correlated four-factor models showed good fit in both sample groups; however, measurement invariance was provided only by the correlated four-factor model. Conclusions: In general, our findings indicate that the use of the full-scale intelligence quotient (FSIQ) score should be used with caution in both low and normal IQ groups and that it would be more appropriate to prefer subscale index scores, especially in educational and clinical assessments.