Using SPSS for Pearson correlation data

Question

I have 3 cohorts that each have data that I have taken the average of different variables within each of the cohorts.

I want to know if one particular variable correlates with the other variables. I have 4 variables total.

I'm using SPSS - I assume I want to run a Pearson Correlation - which I did but it states " cannot be computer because at least one of the variables is constant" which makes me think I have set up my data wrong

Answer 1

If you are getting that message, it means that one of your variables is not actually a variable because it takes on the same value for each case. A Pearson correlation should be used with interval or ratio data, so if your data is ranked or categorical, you should look into a Spearman's correlation or if one variable is continuous, then a biserial correlation or a point-biserial correlation. Let me know if you have additional questions.