Lawrence G. Weiss, PhD

​

Widely acknowledged by psychologists as the gold standard in IQ testing, the Wechsler series of intelligence tests are the most commonly used professional grade IQ tests in the world.  As scientific instruments used to assess the cognitive abilities of children and adults, these tools may only be administered and interpreted by qualified professionals in psychology.  The psychometric quality of these instruments is widely considered second to none. They have been updated based on current research multiple times over the decades.  

​

The Wechsler Adult Intelligence Scales (WAIS) includes the WAIS, WAIS-R, WAIS-III, and WAIS-IV.  The WAIS-V is currently under development.  Dr. Weiss has been responsible for the development of WAIS-III, WAIS-IV, and WAIS-V.  He has authored or coauthored two books about the WAIS-IV.

​

The Wechsler Intelligence Scales for Children (WISC) includes the WISC, WISC-R, WISC-III, WISC-IV, and WISC-V.  Dr. Weiss has been responsible for the development of the WISC-III, WISC-IV, and WISC-V.  He has authored or coauthored five books about the WISC series.

​

The Wechsler Preschool and Primary Scales of Intelligence (WPPSI) includes the WPPSI, WPPSI-R, WPPSI-III, and WPPSI-IV.  Dr. Weiss was responsible for the development of the WPPSI-III and WPPSI-IV.

​

These tests have been translated and adapted into dozens of languages and countries around the world.  Dr. Weiss was responsible for all international adaptation projects since 2000.  He has coauthored a book about Cross Cultural Children's Intelligence.  His research has shown that socio-economic factors account for a majority of the IQ score differences between countries, and between racial / ethnic groups within countries.  Socio-economic variables are believed to be associated with factors that stimulate cognitive development such as educational quality, nutrition, prenatal and postnatal healthcare, etc.