Open AccessA GRAPHICAL APPROACH TO ITEM ANALYSIS
Author(s) -
Livingston Samuel A.,
Dorans Neil J.
Publication year - 2004
Publication title -
ets research report series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.235
H-Index - 5
ISSN - 2330-8516
DOI - 10.1002/j.2333-8504.2004.tb01937.x
Subject(s) - statistics , mathematics , item response theory , equating , smoothing , item analysis , variable (mathematics) , psychometrics , mathematical analysis , rasch model
This paper describes an approach to item analysis that is based on the estimation of a set of response curves for each item. The response curves show, at a glance, the difficulty and the discriminating power of the item and the popularity of each distractor, at any level of the criterion variable (e.g., total score). The curves are estimated by Gaussian kernel smoothing, a weighted moving average process with a parameter that can be varied at the user's discretion. The response curve for the correct answer can be accompanied by curves indicating a confidence region. The response curves also form the basis for estimating item statistics for any group of examinees for which the distribution of the criterion variable is known.