Advanced Guiraud (AG; Daller, van Hout, & Treffers-Daller, 2003)
How Advanced TTR and Advanced Guiraud work
Daller, van Hout and Treffers-Daller (2003) point out that measures based
on frequency lists cannot be applied to those languages for which such
detailed frequency lists are unavailable. To address this issue, they propose
the use of Advanced TTR (ATTR) and Advanced Guiraud (AG), which can be
applied to any language so long as a basic word list is available. ATTR
is calculated by simply dividing the number of advanced types that are
not in the basic word list by the number of tokens. For AG, the denominator
is changed to the square root of the number of tokens. Thus, Daller et
al. (2003) did not propose ATTR and AG as more sophisticated lexical richness
measures than the LFP (Laufer and Nation, 1995) (including the Beyond 2000
measure; Laufer, 1995) or P_Lex (Meara and Bell, 2001), but instead as
Advanced Guiraud = Advanced Type / √Token
Advanced TTR = Advanced Type / Token
Daller et al. (2003) use these measures along with traditional TTR and
the Guiraud index, and compare their effectiveness when applied to the
spontaneous speech productions of two Turkish German bilingual groups,
one German-dominant and the other Turkish-dominant. Their results show
that both ATTR and AG have clear advantages over the traditional measures
(TTR and Guiraud). AG, in particular, very clearly differentiated between
the two bilingual groups.
- Daller, H., van Hout, R., & Treffers-Daller, J. (2003). Lexical richness
in spontaneous speech of bilinguals. Applied Linguistics, 24 (2), 197-222.
- Laufer, B. (1995). Beyond 2000. A measure of productive lexicon in a second
language. In L. Eubank, L. Selinker, & M. Sharwood Smith (Eds.), The current state of interlanguage (Studies in Honor of William E. Rutherford) (pp. 265-272). Amsterdm and Philadelphia, PA: John Benjamins.
- Laufer, B., & Nation, P. (1995). Vocabulary Size and Use: Lexical Richness
in L2 Written Production. Applied Linguistics, 16 (3), 307-322.
- Meara, P., & Bell, H. (2001). P_Lex: A simple and effective way of
describing the lexical characteristics of short L2 texts. Prospect, 16 (3), 5-19.