Multiple UniDimensional unFOLDing
Function for calculating MUDFOLD statistics for a given unfolding scal...
Conditional adjacency matrix (CAM) for dichotomously scored items.
Generic coef method for S3 class "mdf" objects.
MUDFOLD scale diagnostics
Iso statistic for a given unfolding scale.
Max statistic for a given unfolding scale.
MUDFOLD : A nonparametric unfolding item response theory model for dic...
MUDFOLD: Van Schuur's nonparametric IRT model for dichotomous response...
Function for constructing artificial item response data generated unde...
Transform items to preference binary data.
plot function for "mdf" class objects.
print method for "mdf" class objects resulted from the mudfold f...
summary method for S3 class "mdf" objects.
Nonparametric unfolding item response theory (IRT) model for dichotomous data (see W.H. Van Schuur (1984). Structure in Political Beliefs: A New Model for Stochastic Unfolding with Application to European Party Activists, and W.J.Post (1992). Nonparametric Unfolding Models: A Latent Structure Approach). The package implements MUDFOLD (Multiple UniDimensional unFOLDing), an iterative item selection algorithm that constructs unfolding scales from dichotomous preferential-choice data without explicitly assuming a parametric form of the item response functions. Scale diagnostics from Post(1992) and estimates for the person locations proposed by Johnson(2006) and Van Schuur(1984) are also available. This model can be seen as the unfolding variant of Mokken(1971) scaling method.