DOI 10.1007/s10590-005-2467-1 Machine Translation (2005) 19: 37–58 © Springer 2006 Methodologies for Measuring the Correlations between Post-Editing Effort and Machine Translatability SHARON O’BRIEN Centre for Translation and Textual Studies, School of Applied Language and Intercultural Studies, Dublin City University, Dublin 9, Ireland E-mail: sharon.obrien@dcu.ie Abstract. Against the background of a wider research project that aims to investigate the correlation, if any, between post-editing effort and the presence of negative translatability indicators in source texts submitted to Machine Translation (MT), this paper sets out to assess the potential of two methods for measuring the effort involved in post-editing MT output. The first is based on the use of the keyboard-monitoring program Translog; the second on Choice Network Analysis (CNA). The paper reviews relevant research in both machine translatability and MT post-editing, and appraises, in particular, the suitability of think-aloud protocols in assessing post-editing effort. The combined use of Translog and CNA is proposed as a way of overcoming some of the difficulties presented by the use of think-aloud protocols in the current context. Initial results from a study conducted at Dublin City University confirm that triangulating data from Translog and CNA can cast light on the temporal, cognitive and technical aspects of post-editing effort. Key words: post-editing, machine translatability, think-aloud protocol, Translog, choice net- work analysis, controlled language 1. Introduction The aim of this paper is to assess the potential of two methodologies, i.e. keyboard-monitoring using Translog and Choice Network Analysis (CNA), to portray accurately the temporal, technical and cognitive effort involved in post-editing machine translation (MT) output. Research to date on assessing a source text’s suitability for MT and on post-editing is first summarised. The suitability of an alternative method for measuring post- editing effort, i.e. think-aloud protocol (TAP), is considered before the alternative methods of keyboard monitoring and CNA are explained. Some data are then presented which illustrate how these alternative methodolo- gies might be used to meet the research objective.