Abstract
This paper is a critical review of the literature covering the topic of the Wechsler Intelligence Scale for Children – 3rd Edition. The paper will look at the applicability of the instrument for assessing the cognitive abilities of children giving special attention to how the freedom for distractibility index (FDI) is applied. The paper seeks to understand and shed light on the controversy connected with the FD index and how various studies have concluded or recommended about this index.
Introduction
The Wechsler intelligence tests were developed by Dr. David Wechsler after research to develop a universal test for adult intelligence in 1930. Dr. Wechsler held that intelligence was not only global but also depended on a variety of personality aspects. He stated that intelligence was the ability of a person to think rationally, act purposively and deal effectively with his surrounding environment (Mayes & Calhoun, 2004). The Wechsler-Bellevue intelligence scales were the first products of Dr. Wechsler’s research and were based on the fact that most tests administered to adults at the time, were mere adaptations of tests used on children (Andrew, 2010).
From 1939, the Wechsler-Bellevue scales were revised and as a result, three new tests emerged testing adults, children aged between 6 and 16 and preschool children below the age of six. The Wechsler Adult Intelligence Scale (WAIS) was developed in 1955 due to the technical difficulties of Wechsler-Bellevue Intelligence Scales. The WAIS has been updated over the years with the most recent being WAIS-IV released in 2003 (Robert & Dennis, 2009). The second scale developed was the Wechsler Intelligence Scales for Children (WISC). The first WISC was a compilation of several subtests that composed part of the Wechsler-Bellevue Intelligence Scale. The test also included several new subtests especially geared for children. The final intelligence scale was the Wechsler Pre-school and Primary Scale of Intelligence (WPPSI). This test was made for children between 4 years to 6.5 years (Robert & Dennis, 2009).
This study will focus on the Wechsler Intelligence Scales for Children 3rd edition and its effectiveness in measuring the general cognitive ability of children. The WISC-III was developed in 1991 and was in use until 2002 when it was revised into WISC-IV. Although not extensively used nowadays, the WISC-IV is still relatively new hence no extensive research has been carried out on the test (Koyama et al., 2009). The Wechsler Intelligence Scales for Children, third edition (WISC-III) is an individual test based on subtests that do not require writing or reading.
The Wechsler Intelligence Scales for Children is an intelligence test individual administered to children between the ages of ten to sixteen years. It comprises of several tests that are verbal and non-verbal but can be completed without reading or writing. The test produces an intelligence quotient score that represents the cognitive ability of the child. The test requires a qualified psychologist who understands all the terms and components of the test.
The test is divided into the verbal and performance scales. The two scales are further divided into several subsets that make up the four indexes of the test. The WISC-III test has been in existence since the late 1950’s hence an efficient method of administering the test was formed. The Indexes include Verbal Comprehension Index (VCI), Perceptual Organization Index (POI), The Freedom from Distractibility Index (FDI), the Processing Speed Index (PSI).
This paper aims at analyzing the WISC-III tool and providing an overview of its effectiveness to use different tools to yield a conclusive assessment of a child’s intelligence quotient. This study will outline how WISC-III will be used to evaluate children’s intellectual functioning based on Freedom from Distractibility and Processing Speed. The paper will allow one to comprehend the inherent weaknesses of the tool and as such take appropriate measures when using it.
This literature review will focus mainly on the cognitive ability of children. The WISC-III is a tool meant to measure intelligence using a total of 10 subtests. The WISC-IIII is based on the cognitive psychology theories that explore internal mental states. Cognitive psychology centers on internal mental states such as decision making, attention, and motivation, solving problems and thinking capacity.
The WISC-III is usually administered by a trained psychologist and involves asking verbal questions and non-verbal exercises. Two scales are usually used, the verbal and performance scales. In the verbal scales, the children are asked questions divided into several subtests that include information, similarities, arithmetic, vocabulary, comprehension, and coding. In the performance scales, the child is to complete several non-verbal activities and is timed to judge his capabilities. The subtests include picture completion, arrangement of pictures, block design, coding, and object assembly. The two scales are combined to yield the full-scale IQ.
Article Summaries
The WISC-III tool is divided into two scales: the verbal scale and the performance scale. These scales are used to measure four main factors that were later renamed the four main indexes of WISC-III. They include Verbal Comprehension Index (VCI), Perceptual Organization Index (POI), The Freedom from Distractibility Index (FDI), the Processing Speed Index (PSI). According to Kaplan and Saccuzzo (2009), the vocabulary subset is one of the most stable subset and as such, the VCI factor of the test is quite reliable and as various researchers have shown it is quite valid in gauging cognitive abilities of a child. The Perceptual Organization Index (POI) has also been shown to be reliable with a high confidence index with a reliability of r=0.91 (Kaplan & Saccuzzo, 2009). The Freedom from Distractibility and the Processing Indexes have raised several questions as to their ability to accurately rate intelligence and to identify learning disabilities in children.
Various criticisms have been raised about the applicability of freedom from Distractibility index to effectively gauge the cognitive performance of children. Studies carried on the tests vary with researchers focusing on the different ways WISC-III can be applied and how the four indexes vary when applied on a particular group
WISC-III validity across different ethnic and cultural backgrounds, and of different sexual orientation
The studies carried out by Jazayeri (2003) and by Rotsika et al. (2009) aimed to find out whether WISC-III is valid for countries outside America. Jazayeri carried out his study on Iranian children using a sample of 2456 children from 30 different schools. The sample included healthy children, the blind, those with behavioral and attention deficit disorders and the mentally retarded. The WISC-III test was also adapted to Iranian culture where appropriate. Jazayeri (2003) discovered that the test was both reliable and valid in the Iranian context.
He reported a split-half reliability for Full-Scale IQ as 0.96 with the standard error of measurement averaging 3.20, Verbal IQ as 0.95 with the standard error of measurement averaging 3.53 and Performance IQ as 0.91 with the standard error of measurement averaging 4.54. He also found out that most indicators of scale were reliable. The freedom from distractibility and the processing speed indexes were particularly useful in identifying mentally disabled children, those with learning disabilities or ADHD and those suffering from brain trauma. The processing speed index could also be used to discriminate bright normal students from those with high academic progress.
Rotsika et al. (2009) on the other hand sort to study the WISC-III profile of Greek Children with learning disabilities. The study used a sample of 180 children previously diagnosed with learning disabilities. The study found out that the children had a mean Full-Scale IQ of 96.08, a Verbal IQ of 96.38 and a performance IQ of 96.61. When considering individual indexes, the lowest mean scores were for Freedom from Distractibility Index and Processing Speed Index.
The children, however, had a high Perception Organization Index and Verbal Comprehension Index. Rotsika et al. (2009) therefore concluded that the WISC-III index for Greek children suffering from learning disabilities (LD) was similar to other children suffering from the same disorder in English speaking countries. Rotsika et al. (2009) also noted that despite linguistic differences, English and Greek children performed at par thus learning disorders were mainly due to qualitative reasoning and processing speed.
Of specific importance is finding out whether the WISC-III instrument is valid when working with groups from different ethnic and cultural backgrounds. Kush et al. (2001) took a study to find the construct validity of the tool for white and black children and for black children who had been referred to a psychological examination. The researchers noted that in the original WISC-III standardization sample only 15.4% of the sample comprised of black children.
They sampled 1543 white students and 338 black students for this test. For the black students referred for psychological examination, the study sampled 348 students. They found out values for Full-Scale IQ, Verbal IQ, and Performance IQ had a similar factor structure. They concluded that the WISC-III instrument is a strong and valid indicator for intelligence for both white and black students. They noted that there is no evidence of the cultural relativism view of intelligence as proposed by some researchers.
Koyama et al. (2008) sort to study how WISC-III profiles differed between the two sexes. The researchers used the Japanese version of WISC-III on a sample of 26 girls and 116 boys all suffering from high-functioning pervasive developmental disorders. According to the study, the girls had higher scores on the Processing Speed Index coding and symbol search while the boys performed better on block design (POI). Both groups scored low on the verbal comprehension index and freedom from distractibility index. The researches could not draw up a conclusive conclusion and recommended that more tests be carried out to clarify genetic and neurological links to the sex differences.
Practical Uses of WISC-III Freedom from Distractibility Index (FD)
Over the years, WISC-III has been applied in many different ways. Each aspect of the test has been applied to different cases to yield a practical use. Despite initial controversy, the Freedom from Distraction and Processing Speed have been researched and used extensively in various practical uses. In 2008, Freberg et al. carried out a study to determine if WISC-III full-scale IQ can be used to predict future academic achievement.
The clinical study reviewed archival records of a sample of 202 children. The children ranged from the ages of 6 to 13 with a mean age of 8.67. The sample included children from different cultures and mental disability status with 80% having a specific described mental disability. The results showed that the mean IQ was below average. The testing was to determine improvement in English and math scores. The sample was given two tests, three months apart.
The Full-Scale IQ (FSIQ) showed a variance of 44% in the prediction of improvement in reading. For mathematical improvement, the FSIQ was the only aspect that could predict achievement. The interaction between FSIQ and the factor profile status was not significant throughout the test. The findings support the hypothesis that Full-Scale IQ can be used to predict future improvements in performance.
Variability in factor scores could not effectively predict future achievement hence it was necessary to utilize the Full Score IQ achieved by considering all the four factors together. The freedom from Distractibility was, however, one of the most varying factors in the study. Children with behavior and attention deficit disorders such as ADHD showed varying degrees of change concerning Freedom from Distractibility. The researchers concluded the Full-Scale IQ is one of the most powerful psychological tools that can predict academic achievement values.
The results from Freberg et al. (2008) however differ from studies carried out by Robison and Harrison (2005) and by Canivez and Watkins (2001). Robison and Harrison (2005) carried out a study on a sample of 1450 children. They wanted to determine the WISC-III profiles of children referred to or found eligible for special education and gifted programs. They used the eight-core WISC-II subtest profiles identified in the 1991 Wechsler study. They found out that a large percentage of children classified into the subtest profiles did not fit the original Wechsler standardization test.
The researchers thus concluded that psychologists should not carry out routine exploration of the WISC-III profile. Canivez and Watkins (2001) study dealt with the Temporal Stability of WISC-III subtest composite. They choose a sample of 579 children who were tested twice using the tool. They hypothesized that intelligence was a constant trait thus cognitive ability identified through the test should be constant over time. They, however, found the contrary and the subtest based results changed constantly during the test and retest period. They thus concluded that since cognitive results based on the subtest were unreliable, a recommendation as to the child’s cognitive ability was also unreliable.
Oakland, Broom, and Glutting (2000) sort to find out whether a theory proposed by an early research stating that students engaging in inappropriate test-taking behavior will have lower Freedom from Distractibility and Processing speed score when compared to the other factors e.g. verbal comprehension. The study, however, found out that there was no sufficient variability in the scores even when the students engaged in inappropriate test-taking behaviors. They thus recommend that psychologists use another behavioral test when undertaking evaluations on the suitability of a child’s test-taking behavior.
WISC-III FD in children with various disabilities
A study carried out by Mayes and Calhoun in 2004 on children with neurological disorders supported the reliability and validity of WISC-III profile analysis on children with mental disabilities. The study was carried out on children with both neurological disorders and behavioral disorders. The control sample used was children without any perceived disorders. The study was carried out in a clinical setting to figure out whether WISC-III could be used to identify children with neurological disorders.
The study utilized three of the test indexes namely; Perception Organization Index (POI), Processing Speed Index (PSI) and Freedom from Distractibility Index (FDI). The researches then used a simple ranking of the standard scores to carry out their analysis. From the test, it was found out that children suffering from depression, anxiety, and other behavior disorders had results that were common in the control group. There was no distinctive profile noted from this group.
Children suffering from neurological conditions such as Autism, ADHD, and LD, however, displayed distinct profiles that were unique for each neurological condition. Children with autism exhibited low scores in the Freedom from Distractibility Index and also low comprehension (POI). Those with attention deficit hyperactive disorder (ADHD) exhibited low PSI or FDI but had normal Comprehension (POI). Those with brain injuries exhibited low performance (PSI) but did not have low coding or Freedom from Distractibility (FDI). From the results, the authors concluded that WISC-III can be used to create profiles important for clinical personnel to identify various diagnostic possibilities and also allow education intervention where necessary.
Another study carried out by Zander and Dahlgren (2010) also confirmed this fact. The study was carried out on a sample of 240 children having autism, Asperger’s and pervasive developmental disorders. The WISC-II test was reformatted to fit Swedish standards and given to the students. The study found out that there was a distinct difference between children with Asperger’s and those suffering from Pervasive Development Disorders not Otherwise Specified (PDD-NOS) and autism.
Children suffering from Asperger’s performed higher while the other performed below average. Differences between the diagnostic groups also existed mainly in the performance indexes. Children with autism generally had low scores in all the four indexes while those with Pervasive Development Disorders not Otherwise Specified (PDD-NOS) had low scores in the Freedom from Distractibility index and Processing Speed index. Those suffering from Asperger’s syndrome performed relatively better than the rest in all areas but compared with standardized scores, they had low Freedom from Distractibility index. The researchers thus concluded that the WISC-III test is a very good tool to discriminate between the various forms of pervasive development disorders (PDD).
Limitations in the Use of WISC-III Freedom from Distractibility Index (FDI)
Several criticisms have been raised on the issue of using WISC-III. While most scholars and psychologists agree that as a whole the tool is efficient, there are debates as to whether the freedom from Distractibility Index and Processing Speed contribute much to the tool.
A study carried out by Egeland et al. (2006) on the Norwegian translation of WISC-III sought to determine whether or not FDI and PSI indexes were reliable. The study was carried out in a clinical setting whereby 127 children with psychiatric conditions were sampled. The index values for children with pervasive disorders, anxiety, learning disorders, and ADHD were compared. It was noted than of all the indexes, only two had eigenvalues greater than one.
A comparison of the indexes per group showed than children with language disabilities had lower freedom of distractibility index scores that the other indexes. Those with pervasive disorders had lower processing speed when compared to the other indexes while those with ADHD had a stable profile. The researches thus concluded that WISC-III was primarily used to gauge homogenous constructs of intelligence. The study thus questions if the processing speed and the freedom from distractibility contribute much to the identification of cognitive abilities.
The validity of the use of the freedom from disability index (FDI) has also been questioned and criticized by other researchers. Gussin and Javorsky (1995) experimented to compare the FDI values of children with ADHD and those without ADHD. They took a sample of 53 children, 26 having ADHD and 27 healthy children. The study was carried out in a clinical setting with the sample group being given the test and the result being analyzed specifically regarding the FDI index. They found out that there was very little variation in scores between the two groups on the FDI factor. The researchers thus concluded that the Freedom from Disability factor was not a valid classification tool for psychiatric conditions.
These results were replicated by another test carried out in the same year by Anastopoulos, Spito, and Maher (1994). These researchers sort to find out whether the Freedom from Distractibility index is a valid tool for identifying children with ADHD. The study was carried out on 40 children sampled from a group that was referred to a clinic for confirmation of the ADHD disorder. The study used doctoral-level psychologists to administer the WISC-III test.
After an analysis comparing the student scores with the standardized scores and comparing individual performances across all indexes, the researchers found out that the grouped averaged FDI scores were lower than the standardized scores and that individual scores were considerably lower than those from the standardized scores. It was also noted that the FDI factor did not perform well when considered at an individual level. The discrepancies between the verbal comprehension index versus FDI and perceptual organization versus FDI were very few amongst the number of the children sampled. Anastopoulos, Spito, and Maher (1994) thus concluded that the Freedom from Distractibility index should not be used to diagnose ADHD and other methods should be applied.
A test carried out by Sweetland, Reina and Tatti (2006) on possible discrepancies in verbal and performance factors in highly gifted children also cast suspicion on the reliability of the tool. The study sampled 161 gifted children (those with VIQ or PIQ above 130). They found out that there was indeed a larger performance-Verbal score discrepancy than that reported in the WISC-III manual. They attributed this discrepancy to excessive analysis of problems usually carried out by gifted children meaning that they take more time to answer questions. They, however, found out that all in all, the tool can identify the cognitive abilities of these children and that finding the reason of this discrepancy does not alter the reliability of the test.
Critical Evaluation of Psychological Measure
This study was meant to find out whether WISC-III, in particular, the Freedom for Distractibility Index was a valid tool to determine the cognitive abilities of children. Having been operational for 12 years, it is quite accurate to state that the WISC-III test is one of the most accurate tests available to test intelligence. The Freedom from Distractibility and Processing Speed indexes have elicited many debates as to per their validity to measure cognitive abilities and to discriminate against the various learning disorder common in children. The WISC-III tool in itself is widely used all over the world with the term Wechsler IQ denoting the most popular intelligence test known in the world. Until 2008, the WISC-III was the most commonly used tool for measuring the intelligence levels of children.
The WISC-III was designed to test children between the ages of six to sixteen years and 11 months. Wechsler viewed intelligence as performance-driven rather than driven by abilities (Gary, 2009). The tests measure the performance of children according to a predefined set of subtests since Wechsler argued that intelligence capacity is abstract thus its measurement is unreliable.
The WISC-III has been widely used to test the intellectual reasoning of children. The test is composed of two scales verbal and performance scales. According to Michel (2003), the instrument mainly gauges the perceptual association abilities and the verbal understanding of children. The instrument also contains two more aspects: freedom from distractibility and the processing speed. There has however been a lot of debate concerning the ability to efficiently utilize these tools to measure cognitive ability of children. To effectively analyze the usability of the instrument, it is important to determine whether the WISC-III can accurately gauge the Freedom for Distractibility (FD) and the processing speed of children.
Most literature on WISC-III agree that it is the most effective tool used to gauge the intelligence level of children and to determine if a child has a learning disability or intelligence-related disability.
The WISC-III test is universally accepted and has been deemed both ethical and legally accepted as long as parental consent is given and no malicious application of the test occurs. The test is carried out on minors therefore it is necessary to have parental consent. The test scores should not be used to deny a child a fair chance at learning or sports. This can only be agreed upon when consultation with psychologists occurs. The tests have also be found out to be poor discriminative of child with learning disorders or ADHD. It has thus been agreed upon that a child can only be diagnosed with ADHD or other learning disorders after a battery of tests that includes another psychological test in conjunction with WISC-III. Whilst the WISC-III test can be a good indicator of mental disability as a whole, using the Freedom from Distractibility Index to judge whether a child has a learning disorder or ADHD has been criticized as being faulty and invalid.
Ethical Standards in the Study
The American Psychological Association identifies 10 ethical standards that should be met in carrying out psychological studies. In this paper, not all standards are of importance but a few of them have been relevant in selecting literature.
The first important ethical standard is concerning competence. APA requires that studies in the field of psychologists should only be carried out by individuals with prior educational and professional expertise. It also adds that psychologist or researchers undertaking studies where additional factors such as disability, language, sexual orientation, and ethnicity causes a barrier, they should either consult professionals with ample experience with the issue or take additional training. Throughout this paper, the articles chosen were either written by psychology students or qualified psychologist who have undertaken various researches. A total of 12 peer-reviewed articles were chosen from psychology databases and the experience of the authors analyzed by several studies previously carried out and by the number of times an article has been cited in other professional studies.
The next important ethical standard is privacy and confidentiality. Since this study mainly deals with the subject of mental disability and other disorders, it was important to ensure that all articles adhered to this standard. It is the responsibility of a writer to protect confidential information retrieved during the studies. In this paper, the articles chosen had adhered to this principle by ensuring that no names were mentioned. The clinics and schools used in this research were not directly mentioned and no names of the subjects who participated in this study were mentioned.
The third important ethical standard is research and publication. A study has to have institutional approval and informed consent if it is to be ethical, objective and legal. This research involves carrying out tests on children below the ages of 16 therefore both institutional and informed consent was required. The paper chosen are those that stated all the steps they had carried out to ensure that they had informed consent and that the institutions that they were carrying out the research had approved their studies. Of importance was parental consent, allowing the researchers to involve a minor in the research study. All the articles adhered to this standard as such deemed appropriate for this paper.
The final ethical standard is assessment and involves providing valid recommendations and conclusions based on a careful analysis of the collected data. Psychological studies may yield different results when carried out by different people and in different settings. Even though this standard was upheld by the entire list of articles chosen, it can be noted that there were conflicts of recommendations in various studies. This is expected as not all research can be similar and differences in sample size and analysis methods can yield different results.
Psychometric properties
To effectively use a study with any degree of confidence necessitates that it should be reliable, reproducible and valid. Validity and reliability are very important in special cases such as studying mental and learning disorders. The American, Australian, and Canadian WISC-III standardization studies have provided exceptional reliability data for big, heterogeneous children samples. The Wechsler Intelligence Scale for Children-3rd edition manual details test-retest correlation of above.88 for the Intelligence Quotient scores aver 12 days sampling 353 children. While the WISC-III test-retest correction was high, those for factor scales (indexes) and subtests were a bit lower. The table below shows all the reliability data from the WISC manual
Table adapted from Kaplan and Saccuzzo (2009)
Where: VIQ-Verbal IQ, PIQ – Performance IQ, FSIQ – Full-Scale IQ, VC – Verbal Comprehension, PO – Perception Organization Index, FD – Freedom from Distractibility Index, PS – Processing Speed.
The articles chosen met all the criteria for reliability and validity showing impressive values for both test-retest correlation and the standard errors of measurement. The reliability coefficients for all the articles were above 0.70 and the test-retest coefficients being above 0.74 which is relatively high. Most of the articles dealt with different issues and some of them were geared towards that study of children with mental conditions or learning disorders.
Looking through the articles we find that most of the studies had a large sample size except for Gussin and Javorsky who only sampled 53 children. This number is quite low but the researchers took other steps to ensure that reliability and validity were high. They incorporated qualified psychiatrists to administer the test and followed strict rules when carrying out the test. Since they were looking at abnormalities that may arise in the total scores between the two different sexes, the standard error of measurement achieved was acceptable. As stated earlier, all the articles had very high-reliability coefficients r. The study is thus representative of the situation being investigated.
Throughout the study, we have seen the WISC-III instrument being used in a variety of ways. Of concern was how the freedom from distractibility index could be used in different settings. The WISC-III instrument can be utilized in assessing the intelligence quotient of a child. It provides the full-scale IQ which is an analysis of a child’s cognitive ability.
The tool can also be used to identify children who may be suffering from learning disorders or attention deficit disorders or other behavioral disorders. It is however been decided that a child cannot be deemed t be suffering from a mental disorder sorely based on the results of the test but it can be a very good tool to identify those who may be suffering from these disorders. In addition to these, the tool can also be used to monitor the cognitive development of a child throughout successive years. This also allows the tool to monitor academic achievement and to identify areas of weaknesses that a child suffers from.
Conclusion
The Wechsler Intelligence Scale for Children – 3rd edition was widely used from 1991 to 2004. During its twelve years of lifespan, the tool was widely recognized as the most efficient tool to assess the cognitive abilities of children. Most of the subtests and the instrument indexes were recognized as being valid and reliable. However, the controversy surrounding the applicability of the Freedom from Distractibility index (FDI) in assessing the cognitive performance of a child was raised.
This study selected various articles dealing with WISC-II with special attention on how the Freedom from Distractibility index was applied and their conclusion on its applicability. One of the main points of similarity was that the FD index was a valid tool for measuring the intelligence of a child. The FD index was important in assessing the concentration level of a child and the ability of a child to use information previously stored in the brain to solve normal day to day problems.
The FD index was a very important tool in the instrument for providing an assessment of the child’s cognitive ability. Another point of agreement was that the FD index scores were not affected by the sex of the child or by ethnic and cultural backgrounds. While other Indexes were as a result of the environment or upbringing, the FD index was wholly an internal brain process. Male and female students achieved fairly comparable result and no proof could be found to argue that observed differences were a result of sex differences.
Only one major difference was noted in the articles regarding the subject. The main point of controversy in the article was whether the FD index could be used to diagnose learning disorders, ADHD, behavioral disorders and other mental disorders.
The practical implication of WISC-III FD scores can be used for evaluating children’s intellectual functioning and can help create appropriate educational interventions for them, as well as can make a great contribution to the development of children’s psychology and the education of children with disabilities.
From the study, it was noted that a majority of articles supported the use of FD index in identifying mental conditions (5 for, 2 against). Most articles, however, agree that the FDI scores do not perform well on an individual basis thus while it can be used to identify children with mental conditions, it should not be used to diagnose nor to refer a child to a psychiatrist. It was noted that a battery of tests, including the WISC-III, should be used to form a final diagnosis of whether a child is suffering from a mental condition.
The WISC-III tool has been used to test the cognitive abilities of children for 12 years. It has become internationally recognized as the tool of choice in determining the cognitive abilities of children. In my opinion, this tool has been used as intended and has proven to be reliable and valid throughout the years. Kaplan and Stacuzzo (2009) various psychological testing techniques and provided a critical analysis of the Wechsler Intelligence Scale for Children. The reliability and validity data of the WISC-III are very high with the processing speed index having the only medium score when compared to the standards.
From the study, it can be seen that the WISC-III tool is very useful in assessing a child’s cognitive ability. Due to the various controversies surrounding the FD index, the study concludes that the tool is effective in assessing the intelligence of children and in identifying which children have mental disorder nut it is not reliable in diagnosing specific disorders hence by itself, it should not be used as a tool for diagnosing mental disorders.
This study has proven very informational on a variety of topics. First, it has elaborated on the means of testing cognitive abilities and what entails testing of these abilities. The study also has shed light on advanced statistical testing of psychological studies and on how to present, analyze and interpret data from a psychology study. Finally, the study has shed light on the WISC-III instrument, how it is administered and the various subtest and indexes included in the test. As a psychologist, this may prove important when required to administer the test.
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