Wechsler Preschool and Primary Scale of Intelligence – Intelligence Test Tool Review

General Features

The selected intelligence test tool is Wechsler Preschool and Primary Scale of Intelligence;Fourth Edition (WPPSI-IV). This is an all-inclusive clinical tool, anticipated  for evaluating the cognitive operational among kids aged from two years and six months to kids aged seven years to seven months. The WPPSI-IV was written by David Wechsler and it was published by Pearson in 2012. WPPSI-IV is a tool that is individually administered, to be employed by trained examiners with up to Level C assessment training. It is also recommended that the test results may only be interpreted by a professional with adequate training on how to administer and analyze and interpret the results. The WPPSI-IV age range is split into two group bands with the first group including kids aged from 2:6 to 3:11 and the second group involving kids aged from 4:0 to 7:7. The average time of administration for the first group is 27 minutes while that for the second group is 31 minutes (Wechsler, 2012).

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Test Description

The Wechsler Preschool and Primary Scale of Intelligence;Fourth Edition offers comprehensive general assessment of cognitive operation. The test is an integration of three main components that include the ancillary index, the primary index scale (PIS), and the full scale intelligence quotient (FSIQ). FSIQ offers an extra general overview of the cognitive functioning of the child. The primary index scales provide extra comprehensive assessment of the cognitive functioning of a child founded on more narrow abilities.

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On the other hand, ancillary index scales are extra relevant in clinical environment where process-specific and extra domain evaluation are needed, for instance evaluating language delays in a child. The primary index scales and FSIQ are developed from three component scores that include working memory index (WMI), visual spatial, and verbal comprehension for the 2:6 to 3:11 age group, and two extra components that include processing speed index (PSI) and fluid reasoning for the second age group. The WPPSI-IV has replaced the performance IQ and verbal IQ in WPPSI-III with phrases visual spatial index and verbal comprehension index (VCI), respectively while fluid reasoning is a novel scale addition. WPPSI-IV has managed to decrease the test time (Wechsler, 2012).

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Psychometric Properties

The author of WPPSI-IV test presents an all-inclusive assessment of the validity and reliability measures and gives tables containing suitable statistics for results validation. The Wechsler Preschool and Primary Scale of Intelligence;Fourth Edition internal consistency is measured via the split-half technique, and the coefficients were acquired via the formula recommended by previous researchers, based on age groups. The values average coefficient for subtest level performance internal consistency were separately reported for both special groups that include those with expressive language disorder and intellectually gifted as well as the age groups. The average values of coefficient for subtest performance level, including both age groups ranged from excellent with greater than .90 to acceptable with .75. The WPSI-IV measures of reliability for subtests are generally improved or maintained upon the reliabilities of WPPSI-III subtests. At component level, the values of coefficient were established to be between excellent for over .90 and good for .86 ranges, with reliability coefficient for FSIQ being recorded at 0.96, with no important variation between age groups coefficient values, at the component and subtest levels.  The tool was also found to have a high test-retest reliabilities as well as a ranging from 0.75 for acceptable, 0.84 to 0.89 for good and from 0.93 for excellent. A similar result is documented for inter-rater reliability, though with a much higher subtest correlation range of 0.96 to 0.99 (Syeda&Climie, 2014).

The cotemporary principles of assessing the validity of the test depend on various validity evidence lines instead of types. The tool validity was founded on the American standard. Enough efforts were employed to guarantee that the subsets and the items of the WPPSI-IV effectively evaluate what they anticipate to measure. This include comprehensive reviews of the literature and advisory and expert panel reviews were carried out at every stage of research to evaluate the test content and to assess the new subtests and items. This ensured a high level of content validity. In the stage of test development, test writers screened for incorrect response occurring frequency (Syeda&Climie, 2014). The rationales for these poor responses were determined and correction made to improve those aspects. This enhances the response process validity. Internal structure validity was ensured by analyzing the correlation among composite scores. Subtests, andtest items to offer support for its validity. To ensure the test correlation with others, WPPSI-IV test score were assessed in association to past editions of the instrument and associated measures to give advanced support to divergent, convergent, and concurrent validities. All these measures assisted in guaranteeing high instrument validity in assessing children intelligence (Buros, 2014).

The Wechsler Preschool and Primary Scale of Intelligence;Fourth Edition scoring can be conducted using scoring software or by hand. The subtests raw scores can be transformed into two forms of age-corrected scores standard that include composite and scaled scores. The score has standard deviation and mean to assist in gauging a child. Percentile ranks which are based on are also accessible. Practitioners might carry out discrepancy evaluation by contrasting various composite indices and evaluate cognitive weaknesses and strengths of examinees by contrasting a basic index score with the overall performance indicator. The scoring and administration manual is ordered with suitable tabs, and also contains instructions for the verbal administration printed in various font colors. The manual also offers enough sample responses to assist examiners in various differentiating among 2, 1, and 0 point subjective subtest responses and offers guidance on responses of the query. The record forms are designed to mark suitable beginning points for each age group for all subtests, and give the discontinue and reversal rule for every subset, as well as providing accurate response for a few subtests. Moreover, examiners utilize an ink dauber rather than a pencil to cancel and search for bugs, greatly lowering requirements for fine motor on speed tests processing (Wechsler, 2012).

Discussion Items

The WPPSI-IV test for the first age group focuses on determining information they have which measures on receptive vocabulary and naming of the picture as a measure of VCI and GLC and eventually FSIQ. The design block with object assembly as a measure of PRI and later FSIQ, and recognition of pictures, which involve a visit to the zoo as a measure of WMI and FSIQ.The second age group also tested for the same aspects which include information comprising of comprehension, similarities and vocabulary; VCI, design block comprising off object assembly picture concept and matrix reasoning; PRI, picture recognition; WMI, and bug busters which involves cancellation and animal shapes; PSI and receptive vocabulary involving pictures naming. All these, apart from receptive vocabulary are connected to FQSI measures. The full scale basically measures the processing speed, verbal comprehension, working memory, visual spatial, and fluid reasoning for the older group and working memory, visual spatial, and vital comprehension for the younger group. The test provides objective results (Parsons, n.d.).


The ethical issue related to this test is that those who administer it must be well trained on using the test. This highly determines the level of accuracy of the result. Untrained administration may provide biased results that are not a true reflection of the child’s ability. The test result is also highly based on the child’s level of exposure ad growth. The age difference in one group plays a great role in the response provided and thus, it can be highly biased when the result of the child aged 4.0 is compared to a child aged 7, the level of exposure is not the same and neither the level of processing. Thus it can easily give a negative picture of the child ability in case the score comparison standard did not ensure even distribution of the sample based on age.


The test main strength is the availability of the subtest and composites which can assist in measuring specific aspect of intelligence and thus, it is easy to identify the aspect that a child is poor in. The high level of review and refining, being the 4th edition, the instrument has been refined to eliminate constrained noted since the first version was established and thus it is more perfect. It also has provision for children with disability or high intelligence. The main weakness is it may misjudge children at the extreme low age in each group, especially when their performance is compared to those in the extreme high age in each group. However, the test has been highly refined, with high level of validity and reliability and thus, good for its use.

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