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gemma7
08-30-2008, 07:18 AM
Hi

I would like to test for the discriminatory power of the items in my scale using Ferguson's Sigma. Does anybody know how to calculate this value, and whether this (or a good alternative) is possible in SPSS?

I am using this to see whether participant's responses are equally divided among all possible scores, rather than all subjects getting the same score.

Thank you very much!

mp83
08-30-2008, 07:49 AM
Not Ferguson's but helpful I hope

> http://insilico.ehu.es/mini_tools/discriminatory_power/?show=formula