stset with condition | Issue with code

[Girish Venkataraman]

What is wrong with my stset? I am excluding duplicates with the dupdrops variable for outcome analysis where 1 are duplicates.

stset tos, failure(vital==0) if dupdrops == 0

* Example generated by -dataex-. For more info, type help dataex
clear
input byte(dupdrops vital) float tos
0 1  518
0 1 2158
0 1 1966
0 0  482
0 0   24
0 0  304
0 1 1534
0 0  329
0 0  186
1 1 2045
0 0  215
0 0  815
0 0  203
0 0  763
0 0  431
0 0   21
0 1   75
0 0  765
0 1 2645
0 0  262
0 0  327
0 1  182
0 0  162
0 0  138
0 1 1468
0 0 1296
0 0  581
0 1 2726
0 1 2499
0 1   39
0 1  327
1 1    0
0 0   65
0 1    0
0 0  158
0 0   58
0 1   45
0 1 3279
0 1    3
0 0   12
0 0  313
0 0  354
0 0   15
0 1  105
0 0  245
0 1  226
0 0   59
0 1  117
0 1    0
0 1   21
0 0   50
0 0  535
0 0  142
0 1 1784
0 0    6
0 0  461
0 0  360
0 1    0
0 1  919
0 0   15
0 1  741
0 0  138
0 0   91
0 1  182
0 0    8
0 1  366
0 1 1107
0 1    0
0 0  590
0 1  356
0 0   12
0 0  140
0 0  739
0 1   32
0 0  205
0 0  116
0 0  178
0 1    9
0 0  792
0 0  666
0 0  278
0 1   36
0 1 1064
0 1  808
0 0  142
0 0   14
1 1 1123
0 1   50
1 1  433
1 1  456
0 0   42
0 1  370
0 1   21
0 0  141
0 1 1653
0 0  965
0 1 1575
0 1 1315
0 1    0
0 1   70
end
label values vital vitallab
label def vitallab 0 "Dead", modify
label def vitallab 1 "Alive", modify

[Paul Dickman]

-if- is a qualifier, not an option, so is placed before the comma. That is,

stset tos if dupdrops == 0, failure(vital==0)

[Girish Venkataraman]

Love it...Thanks Paul. By the way, I love your tutorial using rcs in survival. Hopefully, I can use it to look at pre-2010 vs post 2010 outcome in this data across multiple countries and time points although I fear I will never know if I am doing things the wrong way.

[Leonardo Guizzetti]

Though it may not have any impact with the data shown in #1, the -stset- manually strongly recommends the use of the -if()- option to restrict records rather than the if qualifier, to remove records in a more safe way.

[Girish Venkataraman]

Though it may not have any impact with the data shown in #1, the -stset- manually strongly recommends the use of the -if()- option to restrict records rather than the if qualifier, to remove records in a more safe way.

How would I use the If() as an option in my situation? that is what I tried first but it kept throwing an error in the code. I was going preserve/restore to exclude certain observations, but that does not seem viable.

[Leonardo Guizzetti]

You were almost correct in your first attempt but if option needs brackets, as indicated in the syntax.

stset tos, failure(vital==0) if(dupdrops == 0)