Dear Dr. Rick,
I am now preforming a logistic regression to estimate propensity score. I have several continuous variables in my predictors and I want to use restricted cubic spline for them in my regression model.
When I wanted manually type in the values that correspond to the 5th, 27.5th, 50th, 72.5th, and 95th percentiles of the test_ecg variable(which means numbers of Electrocardiograms test patient had in previous year), it come out with same value in different percentiles (the output is "0, 0, 3, 7,15").
Then I put this cutpoint into my logistic model with EFFECT statement, the error occurred (log says there can't not be same value for spline), so I am wondering how should I do for this variable.
follow is my coding for information

/*test_ecg*/
proc univariate data=cov.co5_1 noprint;
var test_ecg;
output out=percentiles_test_ecg pctlpts=5 27.5 50 72.5 95 pctlpre=p_; /* specify the percentiles */
run;

data _null_;
set percentiles_test_ecg;
call symput('pctls_test_ecg',catx(',', of _numeric_)); /* put all values into a comma-separated list */
run;

%put &=pctls_test_ecg;

best,
Hank