Introduction
Advanced learners of a foreign language are known to find a number of difficulties not only with respect to accuracy but also phraseologically. They seem to reach a plateau from which it is hard to spring to higher levels of proficiency, which Long (2003) refers to as “a general non-nativelike attainment”. Second language studies have proved there comes a point in foreign language learning when learners seem unable to overcome the obstacles their own performance errors pose to their linguistic development. Adult learners in particular claim they “know” that what they have written is a mistake but only once it has been pointed out by teachers in the feedback do they become aware of it. This phenomenon is not unfamiliar to students at Facultad de Lenguas. In order to address this problem and to help them develop self-reflection and autonomy, teachers of English IV during 2011 encouraged learners to use an Individual Mistake Frequency Log (IMFL hereafter) (Ferris, 2002:332), in which they were invited to record their mistakes, possible corrections and the reference book they might resort to so as to cope with these difficulties. Students were allowed to consult their IMFLs during in-class written assignments and exams. The aim of this study is to evaluate the impact of the IMFL on students‟ written work over time and thus ascertain the degree of grammar reflection learners engaged in, during the experience, as regards their performance in writing. To this effect, 105 written assignments by ten different students are analyzed to track the evolution of a number of specific mistakes, especially those that compromise written communication severely, namely, a) missing subjects, b) the absence of an obligatory determiner and c) incorrect verb patterns including passive participles and unaccussative structures. Likewise, we explore participants‟ answers to a written questionnaire on the use t hey made of the mistake logs and their role with respect to their learning process. In this paper we will present the analysis of the written assignments and the correlation between the mistakes present in these, those recorded individually in the IMFLs and learners‟ perceptions.

Este trabajo se inscribe en el marco del Proyecto de Investigación J023 dirigido por M. Zinkgraf y subsidiado por la Secretaría de Ciencia y Técnica de la Universidad Nacional del Comahue.