1. Examples of item response theory item characteristics curves.
Examples of item response theory item characteristics curves. These three-item information plots provide descriptive information for Likert scale items with five different response options (never, rarely, sometimes, often, always). Higher values for probability (y axis, left) and information (y axis, right), non-overlapping peaks, and a plot that is centered at θ=0 (x axis; θ values should be normally distributed) indicate better item characteristics. The dotted lines indicate overall item information. High and wide is better. Plot (A) provides an example of an excellent item. Plots (B) and (C) provide examples of poor items ([B] = poor discrimination; [C] = poor difficulty).
David T. Selewski et al. CJASN 2017;12:
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