Allyssa M. Lanza is a 2014 graduate of the PsyD Program in Clinical Psychology at Anticch University, New England

Gargi Roysircar, Ph.D., Committee Chair
E. Porter Eagan, Psy.D., Committee Member
Gina Pasquale, Psy.D., Committee Member


WISC-IV, intellectual disability, floor effects, intelligence testing, intellectual assessment

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This study is a pilot re-creation of research in the United Kingdom (UK) by Whitaker and Gordon (2012) that assesses for possible floor effects in the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV). Their study suggested that the Index and Full Scale IQ (FSIQ) scores of low IQ adolescents taking the WISC-IV (UK version) were significantly inflated because low raw scores were converted to scaled scores of 1. Whitaker and Gordon assessed for score inflation and resulting floor effects by creating an alternative scoring system based on the relationship between the lowest raw scores that convert to each WISC-IV scaled score. Since the WISC-IV is the most commonly used intelligence test in school settings in the United States (Riccio, Houston, & Harrison, 1998), similar findings were assessed in the US version of the WISC-IV by completing a pilot replication of the Whitaker and Gordon study. Additionally, I created my own adjusted scoring system that more modestly altered WISC-IV scaled scores. These scaled scores were created based on using the mean of the raw scores that could be converted to each WISC-IV scaled score. The study consisted of 7 de-identified protocols of New England students who obtained a FSIQ less than or equal to 70 and obtained at least one scaled score of 1. Results of the study, however, suggested that Index and FSIQ were not significantly affected by either Whitaker and Gordon’s or my alternative scoring systems. The limitations of the study were the small sample size and related constricted demographics. I concluded that this area of IQ research on intellectual disability warrants investigations with large diverse populations