Inflated N's in Spearman's Rho

Posted by Adam Troy on Apr 04, 2014; 8:47pm
URL: http://spssx-discussion.165.s1.nabble.com/Inflated-N-s-in-Spearman-s-Rho-tp5725316.html

Hi all,

Quick question (I did look for an answer and could not find one). I have a dataset from a nationally representative sample with a column for the weighting of each case which weights the sample to 1,000 total (original sample was 1,003). Weights range from .25 to 5.48 for each case.

When I was running Spearman's correlations (Spearman's rho) with weight cases on I noticed that the N's were being inflated above 1,000 in all cases. For example, in pairs where the pairwise N was 975, the N for the Spearman's rho was 1041. This was not the case when I ran these chi squares with weights applied, which should yield the exact same p value for a comparison of two binary variables. The results also differed from identical weighted Spearman correlation results in SAS.

Any ideas why SPSS was inflate these N's unnecessarily for weighted Spearman correlations? I will be encountering a lot of weighted samples and would like to be able to run all these analyses in SPSS. I'm currently using SPSS 21.

Thanks again,

Adam