John M. Cornwell

Factor Analysis of Ipsative Measures

lpsative measures are multiple measures, where the data are collected, or are modified, in such a way that all subject totals across the measures are equal. Much has been written about factor analysis with such data, however, no clear consensus has been reached regarding the suitability of ipsative measures for factor analysis. The purpose of the present article is to show analytically the fundamental problems that ipsative measures impose for factor analysis. The expected value of the correlation between ipsative measures is shown to equal - 1/ ( k - I), where k is the number of measures. The rank of the resulting correlation matrix is reduced by one to k - 1, and ipsativity alone produces k - 1 artifactual bipolar factors, which will obscure any actual interrelations among the measures. If the data are known to be ipsative or if the tell-tale signs of ipsativity are seen, factor analysis should not be done.

Factor Analysis of the 1985 Revision of Kolb's Learning Style Inventory

Kolbs earlier (1976) Learning Style Inventory (LSI) has been criticized for its poor reliability and validity. Even after revisions (1985) were made and a new instrument was developed, the test-retest reliability remained low. Although construct validity of the original instrument has been often investigated, little work has been done on the revised version. In this study, the responses of 317 subjects who completed the LSI-1985 were factor analyzed. Both a two- and a four-factor solution were examined to assess the adequacy of Kolbs four category description of learning style outcomes. The results afforded support for only two of the individual ability dimensions and little support for Kolbs two bipolar dimensions. Evidence is offered that bipolar dimensions orthogonal to those proposed by Kolb appear to offer a better description of the Learning Style Inventory. The effects of an ipsative scale on determining the factor structure of the LSI are also discussed.

Kolb'S Learning Style Theory Revisited:

The use of nominal-level analysis of four primary learning styles (PLS) (i.e., doing, thinking, watching, and feeling), based on the Learning Style Inventory demonstrated their discriminant/convergent validity but not the validity of Kolbs learning style types (LST) (i.e., accommodator, diverger, converger, and assimilator). The LST typology is derived from the difference of two sets of ipsatively scored variables-a circumstance that contributes to its lack of validity, whereas the PLS categories are based directly on the rank ordering given by subjects. The PLS category, thinking, was associated with having higher scores on a mental ability measure, whereas doing was associated with higher levels of learning and performance on an origami paper-folding task (i.e., an archetypical doing task).

Patterns of neuropsychological deficit in cases of schizophrenia spectrum disorder with and without a family history of psychosis.

This study was designed to identify the types of neuropsychological deficits that are unique to familial and nonfamilial forms of schizophrenia. Seventy-two patients who met Research Diagnostic Criteria for schizophrenia or schizoaffective disorder, mainly schizophrenic, were divided into two groups on the basis of the presence or absence of a family history of psychosis. The two groups were then compared for differences on six neuropsychological parameters as well as for differences in psychotic symptoms. Multivariate analyses indicated that schizophrenic patients with a family history of psychosis showed significantly higher levels of overall neuropsychological deficit and significantly greater deficits on tests of motor-control and abstraction and problem-solving. Factor analyses indicate that schizophrenic patients with a family history of psychosis show a pattern of specific neuropsychological deficits, while schizophrenic patients without a family history show a pattern of more consistent cognitive deficits. The results of this study indicate that recent-onset schizophrenic patients with and without a family history of psychosis show distinctly different patterns of neuropsychological dysfunction. These data suggest that abnormalities in the dorsolateral prefrontal cortex and nonprimary motor areas may be associated with an increased familial risk for psychotic disorder.

A preliminary study of the neuropsychological heterogeneity of familial schizophrenia

This exploratory study describes the heterogeneity of the neuropsychological deficits that characterize familial schizophrenia. Forty-six familial schizophrenics showed significantly more variability in abstraction and problem-solving and motor control than 39 non-familial schizophrenics. Cluster analyses of these two neuropsychological parameters indicate that while the non-familial schizophrenics fall into one homogeneous cluster, the familial schizophrenics fall into three relatively distinct clusters which differ significantly in their morbid risk for schizophrenic-spectrum disorder. These preliminary data suggest that frontal lobe deficits are associated with an increased familial risk for schizophrenia.

Neuropsychological deficits in probands from multiply-affected schizophrenic families

This study was designed to determine if schizophrenics from families with more than one psychotic relative show more severe neuropsychological deficits than schizophrenics with only one psychotic relative, non-familial schizophrenics, and a group of matched normal controls. Eighty-one schizophrenic-spectrum patients were divided into three groups on the basis of the presence of psychotic disorder among first- and second-degree relatives. The three groups of schizophrenics and the normal controls were compared for differences on a brief neuropsychological testing battery. The four groups showed significant multivariate differences. Patients from multiply-affected families showed significantly greater neuropsychological dysfunction on measures of abstract concept formation, visuomotor-coordination, and attention than patients from families that had only one psychotic relative. Schizophrenics from low-density families showed more severe deficits in fine motor-control than non-familial schizophrenics. These data suggest that abnormalities in those frontal systems that are likely to mediate fine motor control and abstract concept formation may be related to the degree of familial loading for psychotic disorder.

Postpubertal disease status in diabetes and factor structure anomaly on the WISC-R

Diabetic children have been found to display an anomalous factor structure on the Wechsler Intelligence Scale for Children-Revised (WISC-R) (Holmes, Cornwell, Dunlap, Chen, & Lee, 1992). The present study sought to extend this finding with a larger cross-regional sample of children to determine which, if any, demographic or disease factor(s) might be related to the anomalous structure. Results revealed that groups of older (> = 12 years) children and those with late disease onset (> = 5 years) exhibited an anomalous four-factor structure in which the traditional Perceptual Organization factor (II) split into two factors: Picture Completion and Picture Arrangement formed a visual discrimination factor; and Block Design and Object Assembly created a spatial conceptual factor. It is postulated that diabetic performance on this visual discrimination factor may reflect mild visual neuropathies, often associated with adolescence and postpubertal disease status.