runolr {lordif}R Documentation

runs ordinal logistic regression models

Description

Runs ordinal logistic regression models and produces DIF statistics and effect size measures

Usage

runolr(rv, ev, gr)

Arguments

rv a response variable
ev an explanatory variable (e.g., conditioning variable)
gr a vector of group identifiers

Details

Model 1: ev Model 2: ev + gr Model 3: ev*gr or equivalently ev + gr + ev*gr

Value

Returns a list of the following components:

chi12 prob for the LR Chi-square comparing Model 1 vs. Model 2
chi13 prob for the LR Chi-square comparing Model 1 vs. Model 3
chi23 prob for the LR Chi-square comparing Model 2 vs. Model 3
beta12 proportional change in the coefficient for ev
pseudo1.CoxSnell Cox & Snell psudo R-square for Model 1
pseudo2.CoxSnell Cox & Snell psudo R-square for Model 2
pseudo3.CoxSnell Cox & Snell psudo R-square for Model 1
pseudo1.Nagelkerke Nagelkerke psudo R-square for Model 1
pseudo2.Nagelkerke Nagelkerke psudo R-square for Model 2
pseudo3.Nagelkerke Nagelkerke psudo R-square for Model 3
pseudo1.McFadden McFadden psudo R-square for Model 1
pseudo2.McFadden McFadden psudo R-square for Model 2
pseudo3.McFadden McFadden psudo R-square for Model 3
pseudo12.CoxSnell Cox & Snell R-square change from Model 1 to Model 2
pseudo13.CoxSnell Cox & Snell R-square change from Model 1 to Model 3
pseudo23.CoxSnell Cox & Snell R-square change from Model 2 to Model 3
pseudo12.Nagelkerke Nagelkerke R-square change from Model 1 to Model 2
pseudo13.Nagelkerke Nagelkerke R-square change from Model 1 to Model 3
pseudo23.Nagelkerke Nagelkerke R-square change from Model 2 to Model 3
pseudo12.McFadden McFadden R-square change from Model 1 to Model 2
pseudo13.McFadden McFadden R-square change from Model 1 to Model 3
pseudo23.McFadden McFadden R-square change from Model 2 to Model 3
df12 df for the LR Chi-square comparing Model 1 and Model 2
df13 df for the LR Chi-square comparing Model 1 and Model 3
df23 df for the LR Chi-square comparing Model 2 and Model 3

Author(s)

Seung W. Choi <s-choi@northwestern.edu>

References

Choi, S. W., Gibbons, L. E., & Crane, P. K. (under review). Development of an iterative hybrid ordinal logistic regression/IRT DIF: A Monte Carlo simulation approach for determining cutoff values. Behavior Research Methods.

Crane, P. K., Gibbons, L. E., Jolley, L., & van Belle, G. (2006). Differential item functioning analysis with ordinal logistic regression techniques: DIF detect and difwithpar. Medical Care, 44(11 Suppl 3), S115-S123.

See Also

rundif, lordif

Examples

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## Not run: runolr(rv, ev, gr)

[Package lordif version 0.1-4 Index]