Web survey mode is likened most closely to traditional mail mode in terms of participant experience. The conventional wisdom for web-based surveys has also borrowed from reminder intervals for mail surveys – i.e. reminders should be sent at weekly intervals (Dillman, 2000), although this view is now evolving (Callegaro, Manfreda, & Vehovar, 2015). With web surveys increasing in popularity exponentially, it’s imperative to explore different reminder intervals to make optimal use of the opportunities of speed afforded by web surveys, without sacrificing data quality. Internal Gallup research indicates that a majority of web respondents respond to surveys within 24-48 hours of getting reminder emails. It might then be appropriate to reduce the interval between reminders for efficiency of data collection, if there are no differences in response rates, respondent characteristics, and substantive answers on the surveys. The present study addressed these questions through a set of experiments investigating the impact of shorter reminder intervals on response rates, composition of respondents and estimates of key questions in each treatment group. The study used data from the Gallup Panel, one of the few probability based mixed mode Panels which maintains demographic profiles of all its members. Eligible panelists were assigned to one of 4 treatment groups based on number of reminders (2 vs. 3) and reminder intervals after initial survey (2 days vs. 3 days). The fifth group was a control group with 2 reminders each one week apart, a schedule typically employed for Panel studies. The findings will explore response rates as well as estimates on various key questions by treatment group and detailed demographic profiles. Non-respondent characteristics and implications for sampling and survey field period decisions will also be discussed.