options pageno=min nodate; title 'Spearman rho and Kendall tau computed on data from perfect monotonic (log) relationship'; data curvi; input x y; y_log=log10(y); cards; 1.0 10 1.9 99 2.0 100 2.9 999 3.0 1000 3.1 1001 4.0 10000 4.1 10001 5.0 100000 proc rank out = transformed; var x y; ranks x_rank y_rank; run; proc print; proc plot; plot y*x y_log*x y_rank*x_rank; proc corr pearson spearman kendall nosimple; var y y_log; with x; run;