Computes scores based on the Vanilla method suggested by Gabel & Huber.
A factor analysis identifies the dominant dimension in the data.
Factor scores using the regression method are then considered as party positions on this dominant dimension.
Usage
vanilla(data, vars = grep("per\\d{3}$", names(data), value = TRUE),
invert = FALSE)
Arguments
data
a dataframe or matrix
vars
variable names that should be used for the scaling (usually the variables per101,per102,...)
invert
invert scores (to change the direction of the dimension to facilitate comparison with other indices) (default is FALSE)
References
Gabel, M. J., & Huber, J. D. (2000). Putting Parties in Their Place: Inferring Party Left-Right Ideological Positions from Party Manifestos Data. American Journal of Political Science, 44(1), 94-103.