Language Variation Suite has added a Varbrul analysis. Varbrul is “an implementation of logistic regression that is used by many sociolinguists” (Keith Johnson, 2008, 174). At present LVS calculates Varbrul weights for a binary dependent variable and categorical independent variables. Varbrul output format is based on chapter 5.7 (K.Johnson,2008): inverse logit (inv.logit) is used from the package gtools. Contrasts option in logistic regression is set to contr.sum. For a binary variable, the calculation is inv.logit(coeficient*1) and inv.logit(coeficient*-1), which outputs weights for two values (e.g. men and women).
Shiny application allows for an interactive quantitative analysis and it is based on R programming language. Since this toolkit is still under development, we will greatly appreciate its evaluation, comments, and feedback!