I am working on a project that is looking at the discriminative properties of 6, 5-point Likert items in a scale. I am using the ltm package in R to examine this within a item response theory (irt) paradigm, using a graded response model (grm).
For each item, I am given a "discrimination value" that corresponds with the slope of the ICC at each level given the ability level. For my six items, the values are (approximately): 2.1, 1.8, 1.3, 0.8, 2.7, 2.3.
How would I interpret these? Is there a cut-off for "good" discriminative properties? Are there values related to "weak", "medium", or "strong" levels of discrimination?
Thanks for your help!