Peekaboo! The Effect of Different Visible Cash Display and Amount Options During Mail Contact When Recruiting to a Probability-Based Panel

Abstract Recent studies consistently showed that making cash visible with a windowed envelope during mail contact increases response rates in surveys. The visible cash aims to pique interest and encourage sampled households to open the envelope. This article extends prior research by examining the effect of additional interventions implemented during mail recruitment to a survey panel on recruitment rates and costs. Specifically, we implemented randomized experiments to examine size (small, large) and location (none, front, back) of the window displaying cash, combined with what part of the cash is shown through the window envelope (numeric amount, face/image), and various prepaid incentive amounts (two $1, one $2, one $5). We used the recruitment effort for NORC’s AmeriSpeak Panel as the data source for this study. The probability-based AmeriSpeak Panel uses an address-based sample and multiple modes of respondent contact, including mail, phone, and in-person outreach during recruitment. Our results were consistent with prior research and showed significant improvement in recruitment rates when cash was displayed through a window during mail contact. We also found that placing the window on the front of the envelope, showing $5 through the envelope compared to $2 and $1, and showing the tender amount compared to the image on the cash through the window were more likely to improve the recruitment rates. Our cost analyses illustrated that the cost difference in printing window versus no window envelope is small. There is no difference in printing cost between front window and back window as they both require custom manufacturing. There is also no cost difference in printing envelopes with small windows versus large windows. Lastly, we found no evidence of mail theft based on our review of the United States Postal Service’s “track and trace” reports, seed mailings sent to staff, and undeliverable mailing rates.