This report contains the results of the 2010 Census Update/Leave Quality Control program. The Update/Leave Operation and the associated Quality Control program occurred in 304 of the 494 Local Census Offices across the United States and Puerto Rico from March 1, 2010 to April 2, 2010. Although termed Update/Leave, the operation was conducted in Type of Enumeration Areas 2 (Update/Leave areas) and 7 (Urban Update/Leave areas), which included areas severely impacted by natural disasters. The Update/Leave universe predominantly consisted of areas where it was difficult to match the mailing address of the housing unit with the location address, such as Post Office Boxes, rural route addresses, and mass mailings to apartment complexes with a single drop point rather than those where mail is delivered to individual apartment mailboxes. The purpose of the Update/Leave Operation was to verify and/or update address information and maps and leave a 2010 Census questionnaire for respondents to mail back to the Census Bureau at every housing unit originally included in the universe and added during the Update/Leave Operation.

The purpose of the Update/Leave Quality Control program was to make sure the Enumerators understood canvassing procedures and to make sure the address list and associated maps were legible and contained all necessary information. The Quality Control program consisted of four components:

• Assignment Area Binder Assembly Check
• Initial Observation of Enumerators
• Dependent Quality Control check of each Assignment Area
• Crew Leader Review and Office Review