Description

The ogive constant can be multiplied by the discrimination parameter to obtain a response curve very similar to the Normal cumulative distribution function (Haley, 1952; Molenaar, 1974). Recently, Savalei (2006) proposed a new constant of 1.749 based on Kullback-Leibler information.

Usage

Format

An object of class numeric of length 1.

Details

In recent years, the logistic has grown in favor, and therefore, this package does not offer any special support for this transformation (Baker & Kim, 2004, pp. 14-18).

References

Camilli, G. (1994). Teacher's corner: Origin of the scaling constant d=1.7 in Item Response Theory. Journal of Educational and Behavioral Statistics, 19(3), 293-295.

Baker & Kim (2004). Item Response Theory: Parameter Estimation Techniques. Marcel Dekker, Inc.

Haley, D. C. (1952). Estimation of the dosage mortality relationship when the dose is subject to error (Technical Report No. 15). Stanford University Applied Mathematics and Statistics Laboratory, Stanford, CA.

Molenaar, W. (1974). De logistische en de normale kromme [The logistic and the normal curve]. Nederlands Tijdschrift voor de Psychologie 29, 415-420.

Savalei, V. (2006). Logistic approximation to the normal: The KL rationale. Psychometrika, 71(4), 763–767.