The Census Bureau first used statistical sampling methods in the 1937 test survey of unemployment ("Enumerative Check Census"). This test survey not only estimated the scope of unemployment in the United States during the Great Depression, but it also served as a "check" on a larger-scale, voluntary census effort attempting to measure the same thing.It was a decade when tens of millions of people in the U.S. experienced mass unemployment and social upheaval as the nation clawed its way out of the Great Depression and rumblings of global war were heard from abroad. Now, intimate details of 132 million people who lived through the 1930s will be disclosed as the U.S. government releases the 1940 census on April 2 to the public for the first time after 72 years of privacy protection lapses. Access to the records will be free and open to anyone on the Internet — but they will not be immediately name searchable.For genealogists and family historians, the 1940 census r...