I have fixed it now thank you, see below, I think I have done it correctly.   data Sim3  ( Drop = Linear_Predict Beta1 Lambda Shape Beta0 Beta1);   Time_Censor = 999999999999999999;  Lambda = 1 ;  Shape = 2;  Do Sim = 1 To 1;  Do n = 1 To 10000 ;  ID + 1 ;  x1=rand('BERN',.5); r=RAND("uniform"); Beta0 = 1; Beta1 = 2; Linear_Predict = Exp(-(beta0* + (Beta1 * x1))) ; Time=(((1/r)-1)**(1/Shape))*(Linear_Predict); If Time_Censor < Time  Then  Do ;  Censored = 1 ;  Time = Time_Censor ;  End ;  Else Censored = 0 ; output; End ; End ; run; ... View more

/* Weibull and Exponential */   %Let Lambda = 1000 ; %Let Shape = 1 ; /* value of 1 for exponential */ %Let Time_Censor = 99999999999999; %Let Beta0 = 1; %Let Beta1 = 1.2; %Let Sn=10; Data Sim1A ( Drop = Linear_Predict Time_Censor Beta1 Lambda Shape Beta0); Lambda = &Lambda. ; Shape = &Shape.; n= 10; Time_Censor = &Time_Censor.; Do Sim = 1 To &Sn. ; Do n = 1 To n ; ID + 1 ; x1=rand('BERN',.5); Beta0=&Beta0.; Beta1=&Beta1.; Linear_Predict = Exp(-(beta0* + (Beta1 * x1))) ; Time = Rand( "WEIBULL", Shape ,Lambda* Linear_Predict) ; If Time_Censor < Time Then Do ; Censored = 1 ; Time = Time_Censor ; End ; Else Censored = 0 ; Output ; End ; End ; Run ;   ... View more