I am running a simple cross tabulation between two nominal variables and using a third (study site location) as a layer. These are Yes/No/unsure answers. In situations where the answers are all "yes" I am unable to get a Chi-Square or P-value. Instead the output returns an error, "No statistics are computed because [variables] are constants."

I did a search and found similar issues in this forum and on one of the IBM forums regarding a Kappa test. The suggestion was to use Sysmis to code the remaining variables. I tried this [Sysmis(variable)] but got very strange numbers, still no Chi Square or P-value, and, of course, the totals were off.

I have an email in to one of the professors at my university, but also wanted to post the question here in the meantime.

How can I rectify this issue? Why would I have to use system missing to code the other answers? I am convinced I did not use the proper syntax as I am used to running simple tests and am using school software and don't have an SPSS book. Further, it seems I may have to split the data set to run the crosstab analysis per site rather than as one major analysis with site delineations (layer 1). Is that a correct assumption?

Thank you for taking the time to read this post. I look forward to learning more!