Overcoming the effects of differential skewness of test items in scale construction.
- Authors: Schepers, J.M.
- Date: 2004
- Subjects: Differential skewness , Scale construction , Test terms , Simplex , Pseudo simplex
- Type: Article
- Identifier: uj:6399 , http://hdl.handle.net/10210/1167
- Description: The principal objective of the study was to develop a procedure for overcoming the effects of differential skewness of test items in scale construction. It was shown that the degree of skewness of test items places an upper limit on the correlations between the items, regardless of the contents of the items. If the items are ordered in terms of skewness the resulting intercorrelation matrix forms a simplex or a pseudo simplex. Factoring such a matrix results in a multiplicity of factors, most of which are artefacts. A procedure for overcoming this problem was demonstrated with items from the Locus of Control Inventory (Schepers, 1995). The analyses were based on a sample of 1662 firstyear university students.
- Full Text:
- Authors: Schepers, J.M.
- Date: 2004
- Subjects: Differential skewness , Scale construction , Test terms , Simplex , Pseudo simplex
- Type: Article
- Identifier: uj:6399 , http://hdl.handle.net/10210/1167
- Description: The principal objective of the study was to develop a procedure for overcoming the effects of differential skewness of test items in scale construction. It was shown that the degree of skewness of test items places an upper limit on the correlations between the items, regardless of the contents of the items. If the items are ordered in terms of skewness the resulting intercorrelation matrix forms a simplex or a pseudo simplex. Factoring such a matrix results in a multiplicity of factors, most of which are artefacts. A procedure for overcoming this problem was demonstrated with items from the Locus of Control Inventory (Schepers, 1995). The analyses were based on a sample of 1662 firstyear university students.
- Full Text:
The power of multiple battery factor analysis in coping with the effects of differential skewness of variables.
- Authors: Schepers, J.M.
- Date: 2004
- Subjects: Multiple Battery Factor Analysis , General Scholastic Aptitude Test
- Type: Article
- Identifier: uj:6361 , http://hdl.handle.net/10210/1105
- Description: The principal objective of the study was to determine the power of Multiple Battery Factor Analysis (MBFA) in coping with the effects of differential skewness of the variables used. Generally speaking, joint analyses result in factors of skewness. To examine the problem the General Scholastic Aptitude Test (GSAT) and Senior Ability Tests (SAT) were jointly applied to a sample of 1 598 first-year university students, and subjected to both a Principal Factor Analysis (PFA) and a MBFA. Three factors were obtained in both instances. The PFA yielded factors of skewness and the MBFA factors of content. The implications of the findings are discussed.
- Full Text:
- Authors: Schepers, J.M.
- Date: 2004
- Subjects: Multiple Battery Factor Analysis , General Scholastic Aptitude Test
- Type: Article
- Identifier: uj:6361 , http://hdl.handle.net/10210/1105
- Description: The principal objective of the study was to determine the power of Multiple Battery Factor Analysis (MBFA) in coping with the effects of differential skewness of the variables used. Generally speaking, joint analyses result in factors of skewness. To examine the problem the General Scholastic Aptitude Test (GSAT) and Senior Ability Tests (SAT) were jointly applied to a sample of 1 598 first-year university students, and subjected to both a Principal Factor Analysis (PFA) and a MBFA. Three factors were obtained in both instances. The PFA yielded factors of skewness and the MBFA factors of content. The implications of the findings are discussed.
- Full Text:
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