Here are some questions as a starting point. Are PAQ605, PAQ620, etc. actually character variables or are they numeric?  If they are character, the usual way to refer to a missing value would be ' ' (not '.')  but if they are numeric it would be advisable to change the data values permanently before doing any other processing. If PAQ605 is 9999, do you want to eliminate the entire observation even if there are valid values for other variables? When you select PAQ635=1, you don't have to check for missing values as well.  If the value is 1, it can't be missing. Start with that much, and your answers will dictate the next steps. Good luck. ... View more