Quantitative behaviour analysis requires the classification of behaviour to produce the basic data. This can be challenging when the theoretical taxonomy does not match observational limitations, or if a theoretical taxonomy is unavailable. Binary keys allow qualitative observation to be used to modify a theoretical taxonomy to produce a practical…

Learning-disabled adults (N=145) participating in vocational rehabilitation were found to constitute a homogeneous group with severe deficits, exhibiting: low-average general intelligence; lower verbal than performance Intelligence Quotients; attention, reasoning, and auditory memory deficits; academic achievement at the fourth/fifth-grade level;…

This study examined the validity and internal and interrater reliability of the Wing Subgroups Questionnaire, an assessment that classifies children with autism into subtypes. Subjects were 42 students (ages 5 to 22) enrolled in multihandicapped special education classrooms. Findings support the reliability and validity of the questionnaire for…

The performance of reading-disabled, math-disabled, slow-learning, under-achieving, and normal-achieving children (total n=143) was compared on verbal and visual-spatial working memory measures under initial, gain, and maintenance testing conditions. Ability group classifications changed under dynamic testing conditions. The study demonstrated the…

Existing estimates of the prevalence of intellectual disability vary substantially between different studies and among different populations (AIHW: Wen, 1997; Roeleveld, Zielhuis, & Gabreels, 1997; Leonard & Wen, 2002), often affected by differences in operational definitions and methods of estimation. For example, in Australia, operational…

This study found that 27 Chinese teachers' perceptions of 196 elementary students nominated as learning disabled or educable mentally retarded (based on identifying characteristics used in the United States) were significantly less favorable than ratings of students nominated as average or gifted. Discriminant analysis yielded 72.19 percent…

This study investigated time allocated to instruction as a function of the specific type of mild handicap and as a function of setting and subject matter content. Subjects were 122 elementary students categorized as learning-disabled, emotionally/behaviorally disturbed, educable mentally retarded, and nonhandicapped. Subjects were in mainstreamed,…

This paper reviews whether Rett syndrome is a subtype of pervasive developmental disorders (PDD). The paper analyzes internal and external diagnostic validity and discusses whether Rett syndrome is a neurological disorder or a mental disorder. The paper concludes that data support the idea of classifying Rett syndrome as a subtype of PDD.…

Critically evaluates recent research aimed at empirical identification of homogeneous subtypes of learning disability. It is suggested that researchers strive for more commonality in the methods and measures used for subtype analysis leading to a single classification scheme to reduce heterogeneity and improve educational efforts. (Author/DB)

Cluster analysis of data from 166 children with autistic spectrum disorders revealed 4 subtypes with differences in behavioral and cognitive areas. The four subtypes include a typically autistic group, a low-functioning group, a high-functioning group (Asperger syndrome/schizoid), and a hard-to-diagnose group with mild/moderate retardation and a…

This study investigated taxonomic clustering and use of frequency associations as features in the semantic memory of children (n=30 in grades two and six) with learning disabilities (LD). Results suggested that, when individual child-generated word lists (i.e., meaningful) are used, children with LD may not be impaired in their ability to utilize…

A total of 274 British youth and adults with handicaps were administered the National Independent Living Skills assessment. Cluster analysis suggested that handicapped persons could be classified into four groups from lowest functioning to highest functioning, using independent living skills variables relating to living, work, and educational…

Concurrent validity testing of the Slosson Intelligence Test-Revised with the Stanford-Binet Intelligence Scale (Fourth Edition), involving 191 individuals (ages 5-69 and IQs of 36 to 110), found a high correlation between the two scales. However, the Slosson unsatisfactorily matched the Stanford-Binet's assignment of individuals to IQ categories.…

This paper compared clinicians' diagnosis and DSM-III (Diagnostic and Statistical Manual), DSM-III-R (Revised), and ICD-10 (International Classification of Diseases) diagnoses of 52 individuals with autism and 62 nonautistic, developmentally disordered individuals. The DSM-III-R system overdiagnosed the presence of autism, and ICD-10 closely…

This study with 22 adults with mild to moderate mental retardation examined the nature of knowledge structures in this population as well as effects of presentation methods and response methods on ability to classify items. Results indicated major effects for disability severity, insignificant findings for presentation method, and a trend toward…