Getting respondents to provide high quality information to open-ended questions in selfadministered surveys is a challenge. The evidence shows visual and verbal design elements play a role in response behavior. Regarding visual design, creating an “optimal” size answer space contributes to higher item response and longer answers in mail and Web surveys (Israel, 2010; Smyth et al., 2009). Likewise, including motivating information in the question stem was shown to improve response quality in Web surveys (Smyth et al., 2009). Finally, mode impacts responses, with Web surveys eliciting longer answers than mail surveys. Given interest in mixed-mode surveys, I explore the effect of adding a motivating prompt to open-ended questions to assess impacts on item response rate and response length for mail and Web modes. Further, I test whether placing the prompt at the beginning or end of the question affects responses. Data from a survey of Cooperative Extension Service clients are used for the study. The importance prompt increased the item response rate for the question about improving Extension’s services but it had no effect on the description question asking clients about getting information, its use and the result. In addition, the importance prompt increased the item response rate for mail surveys but not for Web surveys. I also found that the importance prompt increased the number of words in answers provided by respondents for the improvement question over having no prompt. This effect occurred for the prompt placed either at the beginning of the question or at the end. The importance prompt did not affect response length for the description question. Web responses were longer than mail, independent of the prompt for both questions. The findings suggest there is some benefit to using a motivating prompt but it is unclear when and why it will be helpful.