Lexical Frequency Profiles: A Monte Carlo Analysis

This paper reports a set of Monte Carlo simulations designed to evaluate the main claims made by Laufer and Nation about the Lexical Frequency Profile (LFP). Laufer and Nation claim that the LFP is a sensitive and reliable tool for assessing productive vocabulary in L2 speakers, and they suggest it might have a serious role to play in diagnostic evaluations of learners. The simulations suggest that LFP is not in fact all that sensitive. It works best when the groups being compared have very disparate vocabulary sizes, and is probably not sensitive enough to pick up modest changes in vocabulary size. 1. LEXICAL FREQUENCY PROFILES This paper is a critical analysis of the Lexical Frequency Profile (LFP) approach to estimating productive vocabulary size described in Laufer and Nation (1995). LFP was originally developed by Nation as a way of assessing whether a particular text is suitable for use with learners at a specified level of proficiency. In its simplest form, LFP takes a text as raw input, and outputs a profile that describes the lexical content of the text in terms of frequency bands. In Nation‘s original formulation of LFP (Nation and Heatley 1996), the bands are described as follows: The first [band] includes the most frequent 1000 words of English. The second [band] includes the 2nd 1000 most frequent words, and the third [band] includes words not in the first 2000 words of English but which are frequent in upper secondary school and university texts from a wide range of subjects. All of these base lists include the base forms of words and derived forms. This use of frequency bands to characterize vocabulary is a fairly standard practice in L2 vocabulary studies. There is some disagreement among scholars about which frequency list provides the best standard, but this is really only a serious issue at low levels of frequency. The standard frequency counts are in broad agreement about which words should appear in a ‘first thousand’ or a ‘second thousand’ word list. It might be argued that the words appearing in lists of this sort would be very dependent on context or genre, but in practice this appears not to be the case. LFP in its current incarnation