Kevin S. McGrew

Effects of General and Broad Cognitive Abilities on Mathematics Achievement.

This study investigated the direct and indirect effects of general intelligence and 7 broad cognitive abilities on mathematics achievement. Structural equation modeling was used to investigate the simultaneous effects of both general and broad cognitive abilities on students’ mathematics achievement. A hierarchical model of intelligence derived from the Cattell–Horn–Carroll (CHC) taxonomy of intelligence was used for all analyses. The participants consisted of 4 age-differentiated subsamples (ranging from ages 5 to 19) from the standardization sample of the Woodcock–Johnson III (WJ III; Woodcock, McGrew, & Mather, 2001). Data from each of the 4 age-differentiated subsamples were divided into 2 data sets. At each age level, one data set was used for model testing and modification, and a second data set was used for model validation. The following CHC broad cognitive ability factors demonstrated statistically significant direct effects on the mathematics achievement variables: Fluid Reasoning, Crystallized Intelligence, and Processing Speed. In contrast, across all age levels, the general intelligence factor demonstrated indirect effects on the mathematics achievement variable.

Cattell-Horn-Carroll Cognitive Abilities and Their Effects on Reading Decoding Skills: g Has Indirect Effects, More Specific Abilities Have Direct Effects.

This study employed structural equation modeling to examine the effects of Cattell–Horn–Carroll (CHC) abilities on reading decoding skills using five age-differentiated subsamples from the standardization sample of the Woodcock–Johnson III (Woodcock, McGrew, & Mather, 2001). Using the Spearman Model including only g, strong direct effects of g on reading decoding skills were demonstrated at all ages. Using the Two-Stratum Model including g and broad abilities, direct effects of the broad abilities Long-Term Storage and Retrieval, Processing Speed, Crystallized Intelligence, Short-Term Memory, and Auditory Processing on reading decoding skills were demonstrated at select ages. Using the Three-Stratum Model including g, broad abilities, and narrow abilities, direct effects of the broad ability Processing Speed and the narrow abilities Associative Memory, Listening Ability, General Information, Memory Span, and Phonetic Coding were demonstrated at select ages. Across both the Two-Stratum Model and the Three-Stratum Model at all ages, g had very large but indirect effects. The findings suggest that school psychologists should interpret measures of some specific cognitive abilities when conducting psychoeducational assessments designed to explain reading decoding skills.

The contribution of general and specific cognitive abilities to reading achievement

Since the development of the Weschler scales, significant advances have been made in intelligence theory and testing technology that have the potential to provide a more comprehensive understanding of cognitive abilities than currently exists. For this study, the standardization sample of the Woodcock–Johnson Psychoeducational Battery-Revised (WJ-R)—an empirically supported measure of several constructs within the Cattell–Horn–Carroll (CHC) theory of cognitive abilities—was used to analyze the contribution of specific cognitive abilities to reading achievement at five developmental levels. Structural equation modeling (SEM), with calibration and cross-validation samples, of four different models of the hypothesized relations among the variables was conducted to determine if specific abilities can provide relevant information regarding the development of reading skills. The results of this study clearly indicate that Gc (comprehension knowledge or crystallized intelligence) and Ga (auditory processing) play an important role in the development of reading skills.

Interpreting Intelligence Tests from Contemporary Gf-Gc Theory: Joint Confirmatory Factor Analysis of the WJ-R and KAIT in a Non-White Sample.

In the present study, the correlations of test scores between the Woodcock-JohnsonRevised (WJ-R) and the Kaufman Adolescent and Adult Intelligence Test (KAIT) were factor analyzed in order to test the replicability of the contemporary HornCattell Gf-Gc model in a non-White sample and to gain a more complete understanding of the factorial structure of the KAIT. The empirically supported Gf-Gc theoretical model underlying the WJ-R was used as the criterion against which to evaluate the cognitive abilities that are measured by the KAIT. Participants were 114 6th-, 7th-, and 8th-grade students ranging in age from 10 years, 11 months to 15 years, 11 months. Confirmatory factor analyses were used to evaluate and compare eight a priori factor models and one post-hoc factor model. A Gf-Gc nine-factor model was the most plausible a priori model fit of the WJ-R/KAIT data, a finding that extends the replicability of the Gf-Gc model to a non-White sample. The factorial structure of the KAIT put forward by its authors (i.e., a two-factor Gf-Gc model) was not supported. It appears that the KAIT measures Glr or long-term retrieval (associative memory) and Gsm or short-term memory (memory span) in addition to fluid and crystallized abilities. These results provide support for use of the GfGc theory in a non-White sample and interpreting the KAIT from contemporary Gf-Gc theory rather than a two-factor model.

A Confirmatory Analysis of the Factor Structure and Cross-Age Invariance of the Wechsler Adult Intelligence Scale—Third Edition

In the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; D. Wechsler, 1997), the manual reports several confirmatory factor analyses in support of the instruments latent factor structure. In practice, examiners frequently compare an examinees score from a current administration of the WAIS-III with the results from a previous test administration. Implicit in test-retest score comparisons is evidence that scores retain similar interpretive meaning across time. Establishing an instruments factorial invariance provides the foundation for this practice. This study investigated the factorial invariance of the WAIS-III across the instruments 13 age groups. The overall results from this study generally support both configural and factorial invariance of the WAIS-III when the 11 primary tests are administered.

Why We Can't Say Much about Students with Disabilities during Education Reform:

Education reform initiatives throughout the entire educational system have focused attention on outcomes and quantifiable data. With increasing frequency, the data needed to monitor and evaluate reform initiatives are being drawn from large-scale state and national data collection programs. Although sufficient national level school completion outcome indicators and state goal statements suggest the potential for evaluating the outcomes of students with disabilities, the exclusion of significant numbers of these students from both state and national data collection programs made it all but impossible to describe their status. Recommendations are offered for improving the collection and reporting of information in state and national data collection programs.

Pieces of the Puzzle: Measuring the Personal Competence and Support Needs of Persons with Intellectual Disabilities.

Theoretical and empirical efforts to develop valid methods by which to identify people with mental retardation and related disabilities have been underway for approximately 100 years. Recently, there is a growing consensus that mental retardation is best conceptualized as significant limitations in the multidimensional construct of personal competence. In addition to physical competence, personal competence is conceptualized to include, at the broadest level of conceptualization, the domains of conceptual, practical, and social intelligence. Due to limitations in personal competence, the defining characteristic of persons with mental retardation is an ongoing need for types and intensities of support that most others in society do not require. Current models of personal competence are described and the types of measurement tools available to measure essential dimensions of personal competence are discussed. Additionally, a systematic approach is described for assessing support needs and developing plans to meet these needs.

Factor structure of maladaptive behavior across the lifespan of persons with mental retardation

Data obtained on a sample of persons with mild to profound degrees of mental retardation (N = 8255) and ranging from birth to 98 years of age were factor analyzed to provide information on the structure of maladaptive behavior relative to age and degree of mental retardation. Using the Problem Behavior scales of the Inventory for Client and Agency Planning, two principal factors emerged for children with mild to profound degrees of retardation: Internalized Maladaptive and Externalized Maladaptive. For adolescents and young adults, a three-factor solution which varied by degree of retardation was most appropriate. For middle and older adults, three- and four-factor solutions were identified across all ages and degrees of retardation. Across all samples as many as six different types of dimensions were identified, indicating that the structure of maladaptive behavior may well be influenced by age and level of mental retardation.

Interpretation of the Woodcock-Johnson III Tests of Cognitive Abilities: Acting on Evidence

Publisher Summary This chapter deals with the interpretation of the Woodcock–Johnson III tests of cognitive abilities. The Woodcock–Johnson III Tests of Cognitive Abilities represents the culmination of nearly four decades of systematic psychometric test development. The WJ III COG was developed to provide reliable and valid measures of a number of important cognitive abilities for individuals ranging from preschool-age children to persons in late adulthood. When the accumulated evidence for the validity of the WJ III COG is evaluated within the context of the Standards for Educational and Psychological Testing , it is clear that the WJ III COG has “raised the bar” with regard to state-of-the-art assessment of human cognitive abilities. Because test validation is considered an ongoing process, further research by the test authors and by independent researchers should reveal additional valid uses and interpretations of the battery and, most likely, uses and interpretations that should not be undertaken because little or no validity evidence supports them. Psychologists, educators, and other assessment specialists should continue to seek evidence supporting their interpretations and, when possible, act upon that evidence. Finally, this chapter provides the basis on which these professionals may accomplish these goals.

Improvement in Academic Screening Instruments? A Concurrent Validity Investigation of the K-FAST, MBA, and WRAT-3

The present study examined the extent to which the scores from the K-FAST, MBA, and WRAT-3 are comparable in degree of correlation and mean scores in a sample of university students (N = 62). Results generally provided concurrent validity evidence for the three academic screening tests, although several significant differences were found between measures. An examination of test intercorrelations and test content revealed that the reading and writing domains are not assessed similarly across batteries. The intercorrelations between reading scores were relatively low, ranging from .31 (K-FAST and WRAT-3) to .48 (MBA and WRAT-3). The MBA provides the broadest assessment of reading (word recognition, word comprehension, passage comprehension), followed by the K-FAST. The WRAT-3 Reading test assesses mainly word recognition, as demonstrated by a .68 correlation with the MBA Identification test. The MBA also provides the broadest assessment of writing (punctuation, capitalization, spelling, word usage), followed by the WRAT-3 (which assesses only spelling). The math scores from the three batteries were most consistently correlated (rs ranging from .52 to .54), a finding that supports the validity of the mathematics scores obtained from these instruments. Recommendations for the use and interpretation of the K-FAST, MBA, and WRAT-3 are offered, and avenues for future research are suggested.