James S Fleming | PubMed Health

PubMed2005

TETCORR: a computer program to compute smoothed tetrachoric correlation matrices.

Although many programs exist for computing tetrachoric correlations, these programs typically lack one or more of the following features: (1) efficient processing of a large number of variables and computing of a matrix of coefficients; (2) a matrix-smoothing capability; (3) an accurate, reliable computing algorithm; (4) the ability to handle missing data; and (5) nominal cost. TETCORR, which combines an algorithm developed by Brown (1977) with starting values obtained from Divgi (1979a) for more efficient computation, was created to address these and other user concerns.

Algorithms↗

PubMed2003

Computing measures of simplicity of fit for loadings in factor-analytically derived scales.

A very simple structure is sought when factor analysis is used to develop measurement scales. The SIMLOAD program computes measures of factorial simplicity for rows and columns of loading matrices (usually the factor pattern) as well as some overall measures. These include Kaiser's (1974) index of factorial simplicity for variables (rows), the author's scale fit index for factors (columns), Bentler's (1977) scale-free matrix measure, and hyperplane counts. Routine use of these measures is recommended for multifactor scale development. The measures may also be useful in more general factor applications and in confirmatory as well as exploratory analyses. SIMLOAD also computes factor scale intercorrelations, scale alpha coefficients (including alpha when an item is removed), and sorted loadings for ease of interpretation.

Data Interpretation, Statistical↗