Post-editing (PE) is still a new activity for many translators. The lack of training, clear and consistent guidelines and international standards may cause difficulties in the transition from translation to PE. Aiming to gain a better understanding of these difficulties and using data gathered from a pilot project, this paper explores possible correlations between PE performance and previous translation experience. We test a combination of the LISA QA Model and the GALE post-editing guidelines as a typology for classifying post-editing changes implemented by six post-editors for French and Spanish (three for each target language). This enables a comparison of the types of changes made for the two target languages. We also measure speed and keyboard/ mouse activity and link those to translator experience. The insight gathered may be useful for devising future PE guidelines and training programmes. © 2010 European Association for Machine Translation.