last year i took STATA's introduction to survival analysis course, but they did not spend much time on putting data together for the analysis prior to setting the data. I need help with understanding when to set an observation as a failure. It is obvious that a failure occurs when a subject leaves the program (or dies), but what if they are still in the program when the program ends. When i took the course, i thought we were told that those observations should be left in (assigned a 0 for failure), then STATA would use the rest of the data to kind of project how long those ID's would have stayed in. But when looking at a colleague's SAS program, it looked like she censored this data. ie assigned a 1 to those observations so the were considered failures. Which is correct? or is the answer, it depends. ?