In the spring of 2010, cognitive testing was performed on the mailing pieces associated with the 2010 Census Quality Survey (CQS). The Census Quality Survey (CQS) was conducted in order to estimate measurement error, such as simple response variance, from a census Internet questionnaire compared to that from a census paper questionnaire (Hill, Reiser, & Bentley, 2010). Overall, the mail pieces were understood by participants, although there were some issues, such as inconsistent reasons for the survey being mentioned in different pieces of mail. Where possible, these issues were addressed by the sponsor team before the survey went live.