rundif function

runs ordinal logistic regression DIF

Runs ordinal logistic regression DIF

rundif(item, resp, theta, gr, criterion, alpha, beta.change, pseudo.R2, R2.change, wt)

Arguments

• item: a selection of items to be analyzed
• resp: a data frame containing item responses
• theta: a conditioning (matching) variable
• gr: a vector of group identifiers
• criterion: criterion for flagging (i.e., "CHISQR", "R2", or "BETA")
• alpha: significance level for Chi-squared criterion
• beta.change: proportional change for Beta criterion
• pseudo.R2: pseudo R-squared measure (i.e., "McFadden", "Nagelkerke", or "CoxSnell")
• R2.change: R-squared change for pseudo R-squared criterion
• wt: optional sample weights

Details

The argument item lists the column numbers of the data frame resp to be included in the analysis.

Returns

Returns a list of the following components: - stats: a data frame containing output statistics

• flag: a logical vector of DIF flags

References

Choi, S. W., Gibbons, L. E., Crane, P. K. (2011). lordif: An R Package for Detecting Differential Item Functioning Using Iterative Hybrid Ordinal Logistic Regression/Item Response Theory and Monte Carlo Simulations. Journal of Statistical Software, 39(8), 1-30. URL http://www.jstatsoft.org/v39/i08/.

Crane, P. K., Gibbons, L. E., Jolley, L., and 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.

Author(s)

Seung W. Choi choi.phd@gmail.com

See Also

runolr, lordif

Examples

## Not run: rundif(item,resp,theta,gr)