This web page provides CoSRA to help researchers to rescale the continuous or discrete data to interval scores.

Step 1 Designate the data property of scale scores

Which the scale type below you used? For example, if you use Likert Scale, your scale type is discrete scale; if you use VAS, your scale type is continuous scale.

(1) Enter the number of points on your scale:
(2) Enter lowest score on your scale:
(3) Enter highest score on your scale:
(1) Enter lowest score on your scale:
(2) Enter highest score on your scale:

(3) Specify either the one-parameter or two-parameter model for analyzing your dataset. The continuous rating scale model (Müller, 1987) is referred to as one-parameter model here because it includes one difficulty parameter per item. Verhelst (2019) extended Müller’s model by incorporating both item difficulty and item-level dispersion for each item, which is referred to as the two-parameter model in this context.

(4)
Step 3 Upload your data file based on the template to rescale your data to interval scores and get the result file.
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