300 Lynn Clark and Graeme Trousdale
3.3. Variable Rule Analysis
Tummers, Heylen, and Geeraerts (2005: 246) suggest that “in spite of its
adherence to a maximalistic and usage-based theoretical framework, the use
of advanced statistical techniques as yet turns out to be relatively sparse [in
CL] and subordinate to the theoretical objectives”. And yet, sociolinguistics
has a well established tradition of employing advanced statistical tech-
niques in the empirical analysis of usage data.
Variable rule analysis, or varbrul, is a statistical device that is commonly
used in sociolinguistics to ascertain the effects of various independent fac-
tors influencing the distribution of a dependent variable by means of step-
wise multiple regression^7. It does this by computing the effect of one inde-
pendent variable (or factor group) while explicitly controlling for the
effects of all other known independent variables (Guy 1993: 237). Varbrul
requires discrete variants for both the dependent and independent variables
(or factor groups) and so the researcher must code each factor group (which
contains a number of factors) in this way. The ‘linguistic’ factor groups
coded in this varbrul analysis are provided in Table 1 and the ‘social’ factor
groups are in Table 2.
Table 1. Linguistic factor groups for varbrul analysis of (th)
Linguistic Factor Group Factors
Preceding phon. segment Front vowel / Back vowel / Front consonant / Back
consonant / Pause
Following phon. segment Front vowel / Back vowel / Front consonant / Back
consonant / Pause
Preceding # Present / Absent
Following # Present / Absent
Preceding [f] Present / Absent
Place of (th) (syllable) Onset / Coda
Place of (th) (word) Initial / Medial / Final
Lexical category Place names & proper names / Ordinals / Other
Lexical frequency Low / Low-mid / High-mid / High