News in Proportion takes counts for terms from Chronicling America and maps them by state. This mapping is intended to help users discern places where terms may be particularly significant.
There are wide variations in newspaper coverage for one state versus another. Mapping that focuses on raw counts alone will tend to bury any regional variations for a search underneath the fact that there are just a lot more pages digitized from New York than there are from South Carolina.
Chronicling America is the public interface of the National Newspaper Digitization Program, a joint venture of the National Endowment for the Humanities and the Library of Congress. Grantees in various states work to digitize newspaper "pages representing that state's regional history, geographic coverage, and events of the particular time period being covered". More details about the program can be found here, and here is a full list of the newspapers covered.
News in Proportion searches terms against text that is generated via OCR. As such, the accuracy of counts is limited by the quality of the underlying data. As noted above, some states are represented by a lot of pages while others have far fewer. This discrepancy may affect results in some cases, particularly for infrequently used terms.
Edwin Sperr, M.L.I.S (ed_sperr@hotmail.com)
Clinical Information Librarian
AU/UGA Medical Partnership
Athens, GA
News in Proportion is built on top of the API to Chronicling America. Any questions about the NNDP or the data found therein should be directed towards the Library of Congress.
Communication with the API is handled by jQuery
Maps are generated using the (excellent) GeoChart package that is part of Google Charts.