As response rates to surveys continue to decline (Groves, 2006; Link, Mokdad, Kulp, & Hyon, 2006), researchers have examined a number of factors that might increase respondent cooperation (Singer, Hoewyk, Maher, 2000; Bosnjak & Tuten, 2003). For example, there is a growing body of literature discussing optimal call times for telephone household surveys (Weeks et. al., 1987). With the increasing use of web surveys, it is surprising that there is a paucity of literature about how to increase survey response using paradata, such as the timing of when an email and all reminder notifications are sent to respondents. It may be that when an email notification is sent impacts survey completion rates. It may also be important to send many notifications to prompt survey respondents. In order to address this research question, we alternated the day of the week for sending out email notifications and reminders for a recent web survey conducted for the Advanced Technology Program (ATP) at the National Institute of Standards and Technology (NIST).

For this experiment, individuals were allocated into three groups – email correspondence was sent to Group one on Mondays, Group two on Wednesdays, and Group three on Fridays. Each respondent was sent a survey invitation email and all nonrespondents were sent a maximum of three follow-up reminder emails. Researchers will examine the experimental results to determine: 1) whether a single group generated a higher response rate; and 2) whether the groups differed with respect to the number of reminders required to gain cooperation. Preliminary results suggest that Friday mailings produced higher response rates but required more reminders to achieve this level of cooperation.