The classification field indicates the broad substantive topic(s) that the data cover. Library of Congress subject terms may be used here. PLEASE NOTE A CHANGE IN USAGE INSTRUCTIONS: The string content of the element now contains the language specific label obtained from the controlled vocabulary. This allows for multiple languages through the repeated entry of the "concept" element. See the high level documentation for a complete description of usage.
<topcClas vocab="LOC Subject Headings" vocabURI="http://www.loc.gov/catdir/cpso/lcco/lcco.html" vocabInstanceURI="http://www.loc.gov/catdir/cpso/lcco/lcco#PublicOpinion--California--Statistics">Public opinion -- California -- Statistics</topcClas>
<topcClas vocab="LOC Subject Headings" vocabURI="http://www.loc.gov/catdir/cpso/lcco/lcco.html" vocabInstanceURI="http://www.loc.gov/catdir/cpso/lcco/lcco#Elections--California">Elections -- California</topcClas>