<p> Computing Elapsed Time With SPSS My colleague, Christyn Dolbier, asked me: “I am struggling with how to compute a variable for the time since an event took place. I have the data entered for the date (MM/DD/YY) the event took place and the date (MM/DD/YY) the participants completed the survey. What I want to compute is the amount of time since the event to the date they completed the survey. Do you know of a simple way to do this in SPSS?” I tried to Google an answer to this, without success. Sometimes it is just easier to tinker and figure it out yourself. Here is what I discovered: If you want the elapsed number of days between one date and another, just do this:</p><p>If you just tell SPSS to find the difference between two dates, it will report the answer in SECONDS, so you just divide by 86,400 to get the difference in days. Karl Wuensch, May, 2005. Return to my SPSS Lessons Page.</p>