This chapter discusses research-generated inclusionary criteria for defining dyslexia in children and adults. Writing disabilities, in particular, are under-diagnosed and under-treated and may be an unrecognized contributor to academic failure and school drop-out rates. The International Dyslexia Association (IDA) defines dyslexia as a specific learning disability characterized by unexpected difficulty in accuracy and rate of decoding, word reading and text reading, and spelling. Exclusionary criteria prevent confusion of dyslexia with reading problems having other biological causes. The University of Washington (UW) research team conducted confirmatory factor analyses to evaluate the measurement model based on latent traits underlying multiple indicators or measures of the same process. Current school assessment practices focus on making educational decisions about whether children qualify for special education services rather than on making differential diagnoses. Insufficient attention is given to etiology of reading problems, linking assessment to research-supported effective instruction, and prognosis for long-range outcomes.

The diagnosis of mental retardation can have a profound impact on a person's life. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) distinguishes four categories of mental retardation based on degrees of severity: mild mental retardation, moderate mental retardation, severe mental retardation, and profound mental retardation. The diagnosis of mental retardation requires documentation that an individual displays diminished levels of intelligence as well as significant deficits in adaptive behavior during the developmental period. Adaptive behavior generally refers to a person's ability to meet the standards of personal behavior and independence expected from peers of their age within their culture. Measures of adaptive behavior typically ask respondents who know the person well to indicate whether the person displays important behaviors associated with a variety of adaptive behaviors. Individuals with mental retardation differ in their adaptive skill strengths and deficits and, except for those with severe and profound levels, are unlikely to show significant deficits in all areas of functioning.

To investigate the role of neurocognitive processes related to the acquisition of reading and writing in school-age children, the assessment and instructional research at the University of Washington (UW) is organized around a three-tier model. This research program has three specific aims regarding assessment: (1) identifying research-supported assessment for early identification of at-risk children and early intervention treatments (tier one), (2) developing instructionally based assessment procedures to monitor student responses to modified or supplementary instructions and to identify why some students do not respond to such instructions (tier two), and (3) validating assessment measures for differential diagnosis of specific learning disabilities on the basis of inclusionary criteria (tier three). This chapter focuses on research-supported assessment practices at tiers one and two. The chapter also discusses three kinds of assessment that are relevant at tiers one and two: branching assessment, instructional assessment, and profile assessment. The purpose of branching assessment is to give only the minimum number of achievement and process measures to identify the students who are likely to benefit from supplementary instruction. The purpose of instructional assessment is to monitor the student's responses to an early intervention or general education curriculum modification to determine progress adequacy. The purpose of profile assessment in the primary grades, a developmentally critical period in learning to read and write and do arithmetic is to describe the student's individual profile, on the basis of intellectual abilities, achievement in specific academic domains, and measures of processes related to learning in specific academic domains.

This chapter reviews qualities that may impact a child's test performance and discusses in detail those qualities found through research to have a measurable influence on the performance. An examiner's observations are critical to all features of test use. Their observations enable them to accurately record children's responses to test items. Moreover, information obtained through observations enables examiners to better understand the manner in which children arrive at their answers and to identify cognitive and other personal strengths and weaknesses, thus facilitating test interpretations. Examiners are responsible for ensuring that the testing room provides a comfortable and distraction-free testing environment. Furniture should be of appropriate height and comfortable to the children. Their attention and concentration should not be attenuated by auditory and visual distractions. Language qualities also figure importantly. Most measures of cognitive abilities rely on language to form a bridge between the examiner and examinee, enabling them to communicate. Although the Wechsler Intelligence Scale for Children—Fourth Edition (WISC-IV) is not intended to assess language directly, the quality and nature of children's language can facilitate or impede test use.

This chapter describes current theories and research that informs the psychologist who plays a central role in the initial diagnosis and subsequent assessments of children with attention deficit hyperactive disorder (ADHD). Knowing the overall cognitive ability of a child with ADHD is of relevance in planning behavioral and educational programming. Current theories described in this chapter have, for example, also implicated the significance of working memory impairments in ADHD. The Wechsler Intelligence Scale for Children—Fourth Edition (WISC-IV) also has considerable clinical value for monitoring cognitive changes of paramount importance in determining the efficacy of medical, psychological, and educational programs. Intelligence testing plays an integral role in the assessment process. Intelligence tests like the Wechsler scales are not sufficiently sensitive to be used exclusively in making a diagnosis of ADHD or for discrimination among the various subtypes of ADHD. Clinical and educational needs may require a reexamination of a child's ability in a short span of time to confirm the first test results or to ensure an accurate diagnosis.

This chapter intends to help clinicians understand the unique issues that arise when they use the Wechsler Intelligence Scale for Children—Fourth Edition (WISC-IV) with deaf or hard-of-hearing children. The primary concern confronting examiners who are charged with assessing the intelligence of deaf and hard-of-hearing children is differentially diagnosing intellectual deficits from experiential deficits. Deaf and hard-of-hearing children vary substantially in their means of communication. Slightly more than half (54.9%) of the deaf and hard-of-hearing students in U.S. schools receive instruction using formal sign systems, and slightly less than half (44.5%) are taught exclusively via speech. Examiners must identify relevant communication needs and ensure they accommodate those needs when communicating with and assessing deaf or hard-of-hearing children who rely primarily or exclusively on spoken communication. Given the complexity of these issues, examiners should consider carefully whether they have the competence for assessing deaf and hard-of-hearing children. Research on tests of intelligence using deaf and hard-of-hearing examinees yields a number of findings that examiners should consider when interpreting test scores.

The greater weighting of the Verbal Comprehension and Perceptual Reasoning Factors into the Full Scale score benefits the students with strengths in the higher level cognitive areas. In addition, the separation of speed-based tasks into a separate factor allows students who have strengths in the higher level cognitive demands of the verbal comprehension and perceptual reasoning tasks to demonstrate their skills with time to reflect. Verbal Comprehension has remained very similar to the WISC-III factor of the same name. For the gifted population, the skills required in the Verbal Comprehension factor are traditionally the strongest indicators of giftedness and this was found to be true with the standardization sample. Perceptual Reasoning has changed significantly from the old Perceptual Organization factor. It includes two new core reasoning subtests: Matrix Reasoning and Picture Concepts, in addition to Block Design. All of these subtests were found to discriminate between the gifted and control standardization samples. Although all the factors have undergone some degree of change, the only new factor is the Working Memory Factor. Before looking at the standardization sample, we hypothesized that Working Memory would be a better discriminating factor than Processing Speed for gifted students. Although both Processing Speed and Working Memory did discriminate between the gifted and control samples, in both of these factors there were component tasks for which there were no differences between the two groups.

The Wechsler Intelligence Scale for Children—Fourth Edition (WISC-IV) is used in a variety of ways and for a variety of purposes in research, clinical evaluations, and for other types of assessments and uses. Its strength has been its robustness and its ability to provide valuable information in a wide variety of assessments including neuropsychological assessments, a field that was in its infancy when Wechsler began developing his scales. The WISC-III as a Process Instrument (WISC-III PI) introduced a process based on this approach of assessment developed by Dr. Edith Kaplan and her coauthors. One of the major innovations for WISC-IV is the incorporation of the process approach into the WISC-IV from the beginning. The WISC-IV is published in two versions. The WISC-IV contains the revisions to the core of the test and is the major part of the revision to WISC-III. The WISC-IV Integrated incorporates and expands the process approach to assessment and clinical interpretation from the WISC-III PI and integrates this approach into one manual and a record form, and combined set of stimulus materials for those wishing to incorporate this approach into their assessment tools and technique. This innovation expands the domains of psychological processes assessed by the WISC and provides a useful clinical tool for testing limits, improving clinical and diagnostic sensitivity, and developing intervention strategies. Numerous studies with clinical groups, described in the WISC-IV manual, were undertaken to provide assistance to the clinician when interpreting scores. The WISC-IV has successfully incorporated the tasks that reflect fluid ability, so there is a greater balance in this instrument and the opportunity to observe score differences in subtests that pull more for fluid vs. crystallized intelligence.

This chapter focuses mainly on the Full Scale IQ (FSIQ) and its complement, the General Ability Index (GAI). The comprehensive training of school and child clinical psychologists in assessment, including the use of intelligence tests, the carefully crafted and clearly articulated practice standards and codes of ethics relating to psychological practice in general and assessment more specifically, together with the significant advances in the study of human intelligence and its measurement have done much to quell some of the IQ test controversy. While there is no consensus on the relevance and need for intelligence tests in particular areas of diagnosis, empirical links together with improved diagnostic descriptions certainly contributes to a determination of the clinical relevance of intelligence tests such as the WISC-IV in the identification of and program prescription for children with special needs. In relation to other tests linked with the WISC-IV, the FSIQ in almost all instances shows the highest correlation with subtests tapping both achievement and memory. The FSIQ also correlates more highly with the GRS-S than any of the index scores. While the structure of the WISC-IV together with the suggested profile analyses outlined in the Technical and Interpretation Manual might suggest essentially a top down approach to the test-score interpretations beginning with the FSIQ, this is not strictly the case. The Full Scale IQ score has been the only comprehensive method available within the Wechsler scales for summarizing overall or general cognitive ability.

Children and adolescents with language disabilities form a large heterogeneous group, accounting for 10% to 20% of all children. Language disabilities can be the primary or secondary source of a student's exceptionality, and the impairments can involve different modalities, modes, and dimensions of the language system. There is an ongoing debate regarding how to identify language disabilities and differentiate between specific language impairment (SLI) and language differences as well as whether cognitive referencing is essential or even relevant in the comprehensive assessment of children and adolescents for language disabilities. The controversy of whether to adopt a neutralist perspective or a normative position for the assessment and identification of language disabilities extends into all branches of special education. From the perspective of the clinical or educational diagnostician, the performance patterns on those subtests that contribute to the Verbal Comprehension and Working Memory index scores are of immediate relevance. The Comprehension subtest requires students to give reasons, state the importance and advantages or disadvantages of their actions, characteristics or features, or social expectations for behavior. Students with Mixed Receptive-Expressive language disabilities generally have difficulties in expressing cause-effect relationships and moral judgments.