The 2012 American National Election Study was conducted by the Center for Political Studies of the Institute for Social Research, at the University of Michigan. This study is part of a time-series collection of national surveys fielded continuously since 1948. The election studies are designed to present data on Americans' social backgrounds, enduring political predispositions, social and political values, perceptions and evaluations of groups and candidates, opinions on questions of public policy, and participation in political life.
The sample of the ANES 2012 Time Series Study consisted of a new cross-section of respondents that yielded 5,916 interviews in the pre-election study (2,056 face-to-face and 3,860 on the internet). Of those respondents, 5,513 also completed the post-election interview (1,932 face-to-face and 3,581 on the internet). The samples for the face-to-face and the internet modes were drawn independently from the U.S. population of adults aged 18 and over who were eligible to vote.
For detailed information on the methodology and content of the survey, go to the official ANES site at the University of Michigan. A preliminary version of the full codebook can be found at: http://electionstudies.org/studypages/anes_timeseries_2012/anes2012TS_codebook.pdf