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
rpf.ogive
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.