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The strength of design for this model is 1.#INF0 ?!?

I was running the design efficiency test on a partial profile design in which I have 22 attributes total, rotating 3-19, showing and showing 9. When I run the  test design with 200 respondents and 30% none I'm getting the following at the bottom of the report:

The strength of design for this model is 1.#INF0

Does anyone know what 1.#INFO means? It works fine when I tell it to display eight attributes but nine and ten keep giving me this weird response.
asked Jul 20, 2014 by Mark

1 Answer

0 votes
That number means that the design efficiency couldn't be calculated.  More recent versions of SSI Web have replaced that number with an error message.

This usually results from a divide by zero error when the covariances matrix has very small values.  The causes can be varied, but are related to combination of the attribute set and the number of respondents requested.

If you would like to test showing 9 or ten attributes, try reducing the number of respondents.
answered Jul 20, 2014 by Walter Williams Gold Sawtooth Software, Inc. (18,680 points)