If there is a significant rate of non-response, try to determine how that is influencing the result. Other studies have done things like aggressively go after non-responders to get responses and then associated them with their own group for comparison.
If there is a significant rate of non-response, try to determine how that is influencing the result. Other studies have done things like aggressively go after non-responders to get responses and then associated them with their own group for comparison.