Keeping Track of Panel Members: An Experimental Test of a Between-Wave Contact Strategy

The Panel Study of Income Dynamics (PSID) is a nationally representative longitudinal survey of approximately 9,000 families and their descendants that has been ongoing since 1968. Since 1969, families have been sent a mailing asking them to update or verify their contact information to keep track of their whereabouts between waves. Having updated contact information prior to data collection is associated with fewer call attempts and refusal conversion efforts, less tracking, and lower attrition. Given these apparent advantages, a study was designed in advance of the 2009 PSID field effort to improve the response rate of the contact update mailing. Families were randomly assigned to the following conditions: mailing design (traditional versus new), $10 as a prepaid versus postpaid incentive, timing and frequency of the mailing (July 2008 versus October 2008 versus both times) and whether or not they were sent a study newsletter. This paper reports on findings with regards to response rates to the mailing and the effect on production outcomes including tracking rates and number of calls during 2009 by these different conditions, examines whether the treatment effects differ by key characteristics of panel members including likelihood of moving and anticipated difficulty in completing an interview, and provides some recommendations for the use of contact update strategies in panel studies.