t Japanese-Americans interned in camps after the outbreak of WWII.
"What we'll be able to do now, which we really couldn't do, is to take a look at what the Japanese-American community looked like on the eve of evacuation," said Anderson, a professor of history and urban studies at the University of Wisconsin-Milwaukee.
More than 120,000 enumerators surveyed 132 million people for the Sixteenth Decennial Census — 21 million of whom are alive today in the U.S. and Puerto Rico, according to the U.S. Census Bureau.
The survey contained 34 questions directed at all households, plus 16 supplemental questions asked of 5 percent of the population. New questions reflected the government's intent on documenting the turbulent decade, by generating data on homelessness, migration, widespread unemployment, irregular salaries and fertility decline.
Some of the most contentious questions focused on personal income and were deemed so sensitive they were placed at the end of the survey. Less than 300,000 people opted to have their income responses sealed.
In part because of the need to overcome a growing reluctance by the American public to answer questionnaires and fears about some new questions, the bureau launched its biggest outreach and promotional campaign up to that time, according to records obtained at the Franklin D. Roosevelt Presidential Library and Museum in Hyde Park, N.Y.
It opened its first Division of Public Affairs to blanket the country with its message, reaching out to over 10,000 publications and recruiting public officials, clergy and business owners to promote it.
Movie studios were enlisted to encourage their film stars to participate, including Cesar Romero, who later played the Joker in the Batman television series. A photograph of President Franklin D. Roosevelt taking the census also was used for the campaign.
The bureau also hired the managing editor of "Opportunity: A Journal of Negro Life" to galvanize support in the black community. However, studies in the 1940s revealed undercounts, including 13 percent of draft-age black men.
In a first for the National Archives and Records Administration, the nation's recordkeeper plans to post the entire census on the Internet — its biggest digitization effort to date.
That might be unsurprising given that increasingly popular online ancestry services make vast amounts of genealogical data available. But for previous decennial census releases, researchers had to trek to NARA branches to crank through microfilm machines.
Still, finding a name in the 3.8 million digitized images won't be as easy as a Google search: It could be at least six months after the release before a nationwide name index is created.
In the meantime, researchers will need an address to determine a census enumeration district — a way to carve up the map for surveying — to identify where someone lived and then browse the records.
Some experts said enthusiasm for the release could be dampened by the lack of a name index, especially for novices.
"It may very well frustrate the newcomers," said Thomas Macentee, an industry analyst helping recruit volunteers for a name indexing effort sponsored in part by the Mormon-run FamilySearch.org. "It's like showing up on Black Friday. If you really want that TV set, if you really want that census record, you are going to be ready to go and you are going to keep at it no matter what."
Publicly-traded Ancestry.com, which has over 1.7 million customers, is also working to make the census records searchable by indexing almost all fields and providing proprietary tools to mine the data.
Josh Hanna, a senior adviser for the company, said the 1940 census will be the biggest database of its kind. "It'll be the deepest level of indexing we've ever done," he said. Access to the index and tools will be available for free through the end of 2013.
Other individuals and organizations across the country are also working to ease the use of the records, including the New York Public Library, which is digitizing the full set of New York City's 1940 telephone books to help people 