We are dealing with the challenge of surveying commuters on a college campus. Our approach is going to be to "force" students to respond when they register for spring classes starting around October. This would have respondents answering about their commute over different weeks. For example, grad students get priority registration starting on October 1st and answer the survey. On October 7th, seniors or those with enough credits register and answer the survey, on October 14th juniors register and respond, etc.

My question is whether all responders have to assess their travel over the SAME week or if as long as they are responding about their commute over the previous 5 weekdays with no holidays and within the same season we are ok? Thanks!