Multiple cordial contacts with the student are likely to help you realize a higher overall response rate. Direct, personal, and polite contacts are the best. Such exchanges communicate the message that the student is important to the study's success. Indirect methods such as newspaper ads and flyers will probably have a minimal impact, but using these in combination with your direct methods may be valuable.
Direct methods are costly in terms of time and money.
Below is a list of direct and indirect strategies that you might use to boost response rates. Direct Contacts with Students Call nonrespondents a few days after the mailing of the replacement questionnaire. The idea is to have a personal and polite communication with the student about the survey. These work best if the incentive is received in advance. Send personalized announcement and reminder letters or postcards.