initialize.urfish: initialize.urfish

In austin: A package for doing things with words

Description

Get cheap starting values for a Wordfish model

Usage

initialize.urfish(tY)

Arguments

tY	a document by word matrix of counts

Details

This function is only called by model fitting routines and does therefore not take a wfm classes. tY is assumed to be in document by term form.

In the poisson form of the model incidental parameters (alpha) are set to log(rowmeans/rowmeans[1]). intercept (psi) values are set to log(colmeans) These are subtracted from a the data matrix, which is logged and decomposed by SVD. Word slope (beta) and document position (theta) are estimated by rescaling SVD output.

Value

List with elements:

alpha	starting values of alpha parameters
psi	starting values of psi parameters
beta	starting values of beta parameters
theta	starting values for document positions

Author(s)

Will Lowe

References

This is substantially the method used by Slapin and Proksch's original code.

austin documentation built on May 2, 2019, 5:48 p.m.