Mailed survey follow-ups--are postcard reminders more cost-effective than second questionnaires?

Finding cost-effective ways to increase response to mailed surveys is a concern for many nurse researchers. This study compared two follow-up methods: sending a second questionnaire packet versus sending a reminder postcard to those who did not respond to an initial mailing. Although the second questionnaire yielded a higher response than did the postcard, the cost per additional response was approximately 2 1/2 times higher for the questionnaire than for the postcard when the differential cost of the two mailings is considered.