As the vehicle of data collection, the questionnaire is one of the critical components in achieving high quality in a survey. The best of sampling schemes and estimation strategies will not yield accurate data if the answers provided by the respondent are not meaningful. In recent years, there has been increased emphasis on building quality into the questionnaire design process through pretesting. Methods have been developed or adopted from other fields that focus on the response process, using either the respondent alone or the respondent's interaction with the interviewer as the target of study. Laboratories have been established in the Federal statistical agencies to implement the methods. And generic clearance procedures that foster pretesting of government questionnaires have been established. In this paper, we describe three methods that are used at the Census bureau to pretest questionnaires: cognitive interviewing, behavior coding of respondent/interviewer interaction, and respondent debriefing. Examples of their use in testing Census Bureau survey questionnaires will be presented, and examples of their results will be documented.