Table of Contents
Willis, McBride, Dumont (WMD) Ten-Subtest Intellectual Quotients
for the WPPSI-IV (ages 4:0 to 7:4) and WISC-V
The WISC-V (Wechsler, 2014) changed the Full Scale IQ (FSIQ) from the traditional ten-subtest composite (three Verbal Comprehension, three Perceptual Reasoning, two Working Memory, and two Processing Speed subtests on the WISC-IV [Wechsler, 2003]) to a seven-subtest composite: two Verbal Comprehension (VCI), one Visual-Spatial (VSI), two Fluid Reasoning (FRI), one Working Memory (WMI), and one Processing Speed (PSI) subtests. The new, shorter FSIQ saves a little time and emphasizes Gf and Gc over other abilities. The seven subtests also permit calculation of the Verbal Comprehension, Fluid Reasoning, and General Intellectual Ability (GAI) index scores, but none of the other composites. The WPPSI-IV (Wechsler, 2012) uses only six subtests to calculate a FSIQ.
However, some examiners have been uncomfortable with the briefer FSIQ and at least a few examiners have automatically totaled ten subtests to arrive at a false WISC-V FSIQ inflated by about 43%. Using three more (a total of ten) subtests, examiners gain the ability to calculate the Visual-Spatial, Working Memory, Processing Speed, Nonverbal (NVI), and Cognitive Proficiency (CPI) index scores, but those very productive additional three subtests are not included in the FSIQ.
Examiners may occasionally wish to report a broader composite score based on ten WISC-V or ten WPPSI-IV (ages 4:0 to 7:11) subtests incorporating all of the primary index score subtests and all of the GAI and CPI subtests. This WMD score would be based on more subtests than the FSIQ and would include equal numbers of VC, VS, FR, WM, and PS subtests. If an examiner noticed significant differences between the VS, WM, or PS subtests, the examiner might want to consider the WMD in order to take into account both strengths and weaknesses in the VS, WMI, and/or PS scales.
Ron Dumont created these WMD Ten-Subtest Intellectual Quotient tables for the WISC-V and WPPSI-IV (ages 4:0 to 7:4). These total scores are consistent with the ten-subtest Full Scale IQ of the 2003 WISC-IV and incorporate all of the abilities measured by the primary subtests on each instrument. The scores in these WMD tables must NEVER be presented or interpreted as Full Scale IQs, which are based on seven selected WISC-V subtests and six selected WPPSI-IV subtests at ages 4:0 to 7:4. The WMD scores are global scores based on the ten primary subtests of each instrument. Examiners may find them useful for capturing a broader array of abilities. As with the Full Scale IQ, these scores become less useful, in our opinion, as the range of subtest scores increases.
Unlike the Full Scale IQs and index scores in the test manuals and the additional measures published on-line by Pearson (Wechsler, Raiford, & Holdnack, 2014), these tables were not taken directly from the WISC-V and WPPSI-IV normative data. The tables were constructed from subtest reliabilities and intercorrelations by Ron Dumont, using the Tellegen and Briggs (1967) formula. Scores near the mean should be very close to what would be obtained from the normative data, but may be slightly less accurate toward the extremes.
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Tellegen, A., & Briggs, P. F. (1967). Old wine in new skins: Grouping Wechsler subtests into new scales. Journal of Consulting Psychology, 31, 499- 506.
Wechsler, D. (2003). Wechsler intelligence scale for children (4th ed.). San Antonio, TX: Pearson. (WISC-IV)
Wechsler, D. (2012). Wechsler preschool and primary scale of intelligence (4th ed.). Bloomington, MN: Pearson. (WPPSI-IV)
Wechsler, D. (2014). Wechsler intelligence scale for children (5th ed.). Bloomington, MN: Pearson. (WISC-V).
Wechsler, D., Raiford, S. E., & Holdnack, J. A. (2014). Wechsler intelligence scale for children (5th ed.): Technical and interpretive manual supplement: Special group validity studies with other measures and additional tables. Bloomington, MN: Pearson. Retrieved from WISC 5 Technical and Interpretive Manual Supplement: Special Group Validity Studies With Other Measures and Additional Tables (Click on link to download)
Wechsler Preschool and Primary Scale of Intelligence, Wechsler Intelligence Scale for Children, WPPSI-IV. WISC-IV, and WISC-V are trademarks of Pearson, Inc. and its affiliates. The tests, contents, and associated materials are copyrighted by Pearson, Inc. and its affiliates. These notes and the linked tables are derived from Pearson’s published norms tables for the WPPSI-IV (Click here for WPPSI IV Test Ordering Information) and the WISC V (Click here for WISC V Test Ordering Information) Neither the explanation above nor the tables below have been reviewed or approved by Pearson, Inc., or any of the test’s authors.
WPPSI-IV WMD Intellectual Quotient Based on Ten Primary Subtests
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For a printable copy of this entire table, click here on WPPSI-IV-WMD-based-on-10-Primary or click on the image below.
WISC-V WMD Intellectual Quotient Based on Ten Primary Subtests
For a printable copy of this entire table, click here on WISC-V-WMD-based-on-10-Primary or click on the image below.
