Calculates the crossed probabilities associated with the numerator and denominator of the odds-ratio under dichotomous IRT models
CrossedProbabilities(thetaValue, itemParameters, logistic, irtModel = "3pl")
A numeric value or array for the theta (ability) value(s) for which the odds will be calculated
A list containing the "focal" and "reference" item parameters. Item parameters are assumed to be on the same scale.
A logical indicating whether the logistic or the normal metric should be used.
A string stating the irtModel used. May be one of "1pl", "2pl", or "3pl".
out A list containing the crossed products for the 'num' the numerator, 'den' the denominator for the odds-ratio, and 'or' the odds-ratio
Roussos, L., Schnipke, D. & Pashley, P. (1999). A generalized formula for the Mantel-Haenszel Differential Item Functioning parameter. Journal of educational and behavioral statistics, 24(3), 293--322. doi:10.3102/10769986024003293