When writing survey questions, researchers who want to maximize response rates, reliability, and validity can choose among a variety of response formats. Among these formats are checkboxes, where a respondent can check off one or more answers from a provided list, and yes-no radio buttons, in which each item must individually be clicked as a positive or negative response. Previous research shows consistently that asking questions in a yes-no format yields higher endorsements than in a checkbox format. Despite these consistent results, however, there is not enough evidence to demonstrate which of the two forms is closer to the “truth.” In this paper, we examine the results of two web survey experiments conducted on Google advertisers in which the respondents were randomly assigned to view either a checkbox list or an analogous series of questions with yes-no answer response options. The results from the first survey (conducted earlier this year) confirm the previous findings that yes/no questions yield greater endorsement rates in comparison to checkboxes. In the second, forthcoming survey (to be completed in the first quarter of 2012), we will be able to connect each response to internal information indicating the behavior of that specific respondent/advertisers. Using these objective measures of behavior, we will validate the responses of each experimental condition to determine whether checklists underestimate endorsements, or yes-no radio buttons overestimate them (or both).