May 28, 2022

New Research Article: “The Impact of OCR Quality on the Use of Digitized Historical Newspapers”

The following article appears in the latest issue (2014: 8.1) of DHQ: Digital Humanities Quarterly.


Mining for the Meanings of a Murder: The Impact of OCR Quality on the Use of Digitized Historical Newspapers


Carolyn Strange
Australian National University

Daniel McNamara

Josh Wodak
Australian National University

Ian Wood
Research School of Computer Science, Australian National University


DHQ: Digital Humanities Quarterly


Digital humanities research that requires the digitization of medium-scale, project-specific texts confronts a significant methodological and practical question: is labour-intensive cleaning of the Optical Character Recognition (OCR) output necessary to produce robust results through text mining analysis?

This paper traces the steps taken in a collaborative research project that aimed to analyze newspaper coverage of a high-profile murder trial, which occurred in New York City in 1873.

A corpus of approximately one-half million words was produced by converting original print sources and image files into digital texts, which produced a substantial rate of OCR-generated errors. We then corrected the scans and added document-level genre metadata. This allowed us to evaluate the impact of our quality upgrade procedures when we tested for possible differences in word usage across two key phases in the trial’s coverage using log likelihood ratio [Dunning 1993].

The same tests were run on each dataset – the original OCR scans, a subset of OCR scans selected through the addition of genre metadata, and the metadata-enhanced scans corrected to 98% accuracy. Our results revealed that error correction is desirable but not essential. However, metadata to distinguish between different genres of trial coverage, obtained during the correction process, had a substantial impact. This was true both when investigating all words and when testing for a subset of “judgment words” we created to explore the murder’s emotive elements and its moral implications. Deeper analysis of this case, and others like it, will require more sophisticated text mining techniques to disambiguate word sense and context, which may be more sensitive to OCR-induced errors.

Direct to Full Text Article

Direct to Complete TOC (DHQ; 2014:8.1)

About Gary Price

Gary Price ( is a librarian, writer, consultant, and frequent conference speaker based in the Washington D.C. metro area. Before launching INFOdocket, Price and Shirl Kennedy were the founders and senior editors at ResourceShelf and DocuTicker for 10 years. From 2006-2009 he was Director of Online Information Services at, and is currently a contributing editor at Search Engine Land.