plot.DIF_stats function

plot method for pairwise DIF statistics

## S3 method for class 'DIF_stats'
plot(
  x,
  items = NULL,
  itemsX = items,
  itemsY = items,
  cluster = FALSE,
  alpha = 0.05,
  ...
)

Arguments

• x: object produced by DIF
• items: character vector of item id's for a subset of the plot. Useful if you have many items. If NULL all items are plotted.
• itemsX: character vector of item id's for the X axis
• itemsY: character vector of item id's for the Y axis
• cluster: arrange items by similarity.
• alpha: significance level used to color the plot (two sided)
• ...: further arguments to plot

Details

Plotting produces an image of the matrix of pairwise DIF statistics. The statistics are standard normal deviates and colored to distinguish significant from non-significant values. If there is no DIF, a proportion alpha off the cells will be colored significant by chance alone.