This study was conducted to evaluate several potential improvements in the 2010 Decennial Census mail form:

• A revised instruction about whom to list as Person 1,
• A Final Question series intended to reduce and identify coverage errors, and
• A deadline f or return of the form, combined with a compressed mailing schedule.

Westat conducted a national mailout test for the Census Bureau in March and April of 2006. Census questionnaires were mailed to a national sample of addresses on the U. S. Postal Service Delivery Sequence File; Austin TX was excluded to avoid interfering with a census test in that city. Sampled households received an advance letter, an initial questionnaire package, and a thank you/reminder postcard. There was no replacement questionnaire and no follow up for nonresponding households.

Three experimental factors were evaluated in four panels, with 7,095 sample addresses allocated to each panel. A total of 13,703 questionnaires were returned by the cutoff date of May 19, with response rates varying from 50 to 53 percent among panels. A sample of about 600 cases was sent for a Coverage Followup (CFU) interview in order to assess the Final Question series. CFU interviews were conducted by telephone during July of 2006; the response rate was 82 percent.