Since 2008, Gallup has been conducting 1,000 surveys daily using a dual-frame RDD and cell phone sampling. With an annual sample of approximately 355,000 respondents, this research undertaking affords a great opportunity to tap into an already-cooperative, nationally representative sample for additional research studies. Every survey respondent is asked if they would be willing to be recontacted “to learn a bit more about their thoughts and opinions.” Typically, about 50% agree to be recontacted.

In the fall of 2009, Gallup was asked to leverage this recontact sample to conduct a follow-up mail/web survey regarding international travel. An experiment was designed to test various methods to maximize willingness to be recontacted and to provide a mailing address or email address, as well as to boost actual response rates to the follow-up survey. Over the course of 38 days of data collection, an experiment was conducted with three treatments. Each treatment had three conditions to which all daily survey respondents were randomly assigned. The first treatment tested various tailored messages to seek the respondent’s initial agreement to be recontacted based on their responses to substantive items in the telephone survey (such as “We are specifically hoping to follow-up with people like you who are…”). The second treatment tested different messages regarding the average time to complete the follow up study. The final treatment sought to determine the most effective sequence of questions to assign the respondent to either the mail or Web mode in order to maximize the number of valid email and/or mailing addresses provided.

The findings will help improve the size and performance of recontact sample from a large, nationally representative telephone sample.