Fit Graph of Steps

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This graph is similar to the Fit Graph of Items, except that it displays infit mean squares of step parameters for partial credit models or of tau parameters for rating scale models. Note the difference in the labels along the y-axis. An example is shown in Figure 1.

  1. Select Reports - Item Reports – Fit Graph of Steps from the main menu.
  2. You will be presented with a dialog window. Enter values for the options and click on OK.
    Figure 1. Fit Graph for Steps for Example 2 demo.
    As shown in Figure 1, the graph display the infit mean square values for individual item parameters rather than for the item averages. Here, it appears that the step difficulties that will be used for proficiency estimation are a good fit to the model; their mean squares are all very close to 1.0.
  3. Select File – Save As JPG or File – Save As PNG. Each tab on the graph will be saved as a separate graphic file, using the name on the tab.
  4. Print the graphic using File – Print.
  5. Close the window by clicking on the OK button.