Thank you for your response. The data and code can be found from https://documentation.sas.com/doc/en/statug/15.2/statug_phreg_examples10.htm data Bladder; keep ID TStart TStop Status Trt Number Size Visit; retain ID TStart 0; array tt[4] T1-T4; infile datalines missover; input Trt Time Number Size T1-T4; ID + 1; TStart=0; do Visit=1 to 4; if tt[Visit] = . then do; TStop=Time; Status=0; end; else do; TStop=tt[Visit]; Status=1; end; output; TStart=TStop; end; if (TStart < Time) then delete; datalines; 1 0 1 1 1 1 1 3 1 4 2 1 1 7 1 1 1 10 5 1 1 10 4 1 6 1 14 1 1 1 18 1 1 1 18 1 3 5 1 18 1 1 12 16 1 23 3 3 1 23 1 3 10 15 1 23 1 1 3 16 23 1 23 3 1 3 9 21 1 24 2 3 7 10 16 24 1 25 1 1 3 15 25 1 26 1 2 1 26 8 1 1 1 26 1 4 2 26 1 28 1 2 25 1 29 1 4 1 29 1 2 1 29 4 1 1 30 1 6 28 30 1 30 1 5 2 17 22 1 30 2 1 3 6 8 12 1 31 1 3 12 15 24 1 32 1 2 1 34 2 1 1 36 2 1 1 36 3 1 29 1 37 1 2 1 40 4 1 9 17 22 24 1 40 5 1 16 19 23 29 1 41 1 2 1 43 1 1 3 1 43 2 6 6 1 44 2 1 3 6 9 1 45 1 1 9 11 20 26 1 48 1 1 18 1 49 1 3 1 51 3 1 35 1 53 1 7 17 1 53 3 1 3 15 46 51 1 59 1 1 1 61 3 2 2 15 24 30 1 64 1 3 5 14 19 27 1 64 2 3 2 8 12 13 2 1 1 3 2 1 1 1 2 5 8 1 5 2 9 1 2 2 10 1 1 2 13 1 1 2 14 2 6 3 2 17 5 3 1 3 5 7 2 18 5 1 2 18 1 3 17 2 19 5 1 2 2 21 1 1 17 19 2 22 1 1 2 25 1 3 2 25 1 5 2 25 1 1 2 26 1 1 6 12 13 2 27 1 1 6 2 29 2 1 2 2 36 8 3 26 35 2 38 1 1 2 39 1 1 22 23 27 32 2 39 6 1 4 16 23 27 2 40 3 1 24 26 29 40 2 41 3 2 2 41 1 1 2 43 1 1 1 27 2 44 1 1 2 44 6 1 2 20 23 27 2 45 1 2 2 46 1 4 2 2 46 1 4 2 49 3 3 2 50 1 1 2 50 4 1 4 24 47 2 54 3 4 2 54 2 1 38 2 59 1 3 ; title 'Intensity Model and Proportional Means Model'; proc phreg data=Bladder concordance covm covs(aggregate); model (TStart, TStop) * Status(0) = Trt Number Size; id id; where TStart < TStop; run; ... View more

Yes, kind of. Could you help me figure it out? Many thanks. ... View more

Thank you for your help. Here is the SAS code. The cubic splines variables: weight and horsepower have percentiles 25% and 75% with degree=3. proc print data=sashelp.cars(obs=10); run; data cars; set sashelp.cars; keep mpg_city weight Horsepower; run; proc glmselect data=cars outdesign(addinputvars fullmodel)=SplineBasis; effect spl = spline(weight Horsepower/ naturalcubic basis=tpf(noint) knotmethod=percentilelist(25 75) degree=3); model mpg_city = spl / selection=none noint; quit; The result is shown below. However, the spline variables: weight and horsepower only have one coefficient? Should they have four coefficients for each variables as they are cubic splines (X^3, X^2, X, and constant)? How to control the knots and how many knots are required for this analysis? Could you help me figure it out? Many thanks!   ... View more

I wonder if I can just use the data with the spline variable age (or weight) created by R and then run the model instead of using the effect statement. However, the results of the coefficients and the confidence intervals look different using R and SAS effect statement. ... View more

Many thanks for both your help. Here is the effect statement I used to create the spline age. effect spl = spline(age / naturalcubic basis=BSPLINE knotmethod=percentilelist(25 75) ); I wonder if I can just use the data with the spline variable age (or weight) created by R instead of using the effect statement and then run the model using SAS. However, the results of the coefficients and the confidence intervals look different using SAS and R.    Also, I wonder if the spline age has two categories?     ... View more

I want to create cubic spline terms for a continuous variable such as age, using the 25th and 75th percentiles as knots. For R, I could use the code library(splines) age_25 <- quantile(data$age, 0.25) age_75 <- quantile(data$age, 0.75) # Generate cubic spline terms data$age_spline <- bs(data$age, knots = c(age_25, age_75), degree = 3) Please let me know if further details are needed. Many thanks     ... View more

Thanks but how to remove x and y of the annotation in the legend? I may have other variables in the data. So how to remove x and y of the annotation in the legend but keep other variables in the legend? ... View more

Awesome, Many thanks! ... View more