iccplot function

Item Characteristic Curve Plot

Plots an item characteristic curve under the two-parameter logistic model.

iccplot(b, a)

Arguments

• b: a single number representing the value of item difficulty.
• a: a single number representing the value of item discrimination.

Details

While the theoretical range of ability is from negative infinity to positive infinity, practical considerations usually limit the range of values from -3 to +3.

Examples

iccplot(0, 1)
iccplot(a = 1, b = 0)
iccplot(0, 1); par(new = TRUE); iccplot(-1.5, 1)

References

Baker, F. B., & Kim, S.-H. (2017). The basics of item response theory using R.

New York, NY: Springer. ISBN-13: 978-3-319-54204-1