logmult (version 0.7.4)

HMSkew: Specify a Skew-Symmetric Association in a gnm Model Formula

Description

A function of class "nonlin" to specify a van der Heijden & Mooijaart (1995) skew-symmetric association in the formula argument to gnm.

Usage

HMSkew(row, col, inst = NULL)

Arguments

row

the levels of the row variable

col

the levels of the column variable

inst

a positive integer specifying the instance number of the term

Value

A list with the required components of a "nonlin" function:

predictors

the expressions passed to Mult

term

a function to create a deparsed mathematical expression of the term, given labels for the predictors.

call

the call to use as a prefix for parameter labels.

Details

This function is used by hmskew to fit skew-symmetric models proposed by van der Heijden & Mooijaart (1995) and their variants. It can be used directly to fit custom variants of the model not supported by hmskew.

This function combines its arguments in the following way: $$ HMSkew(i, j) = \nu_i \mu_j - \mu_i \nu_j $$ where \(HMSkew(i, j)\) is the skew association for the cell at the intersection of row i and column j of the table. See reference for mathematical details.

References

van der Heijden, P.G.M., and Mooijaart, A. (1995). Some new log bilinear models for the analysis of asymmetry in a square contingency table. Sociol. Methods and Research 24, 7-29.

See Also

hmskew

Examples

# NOT RUN {
  # See ?hmskew.
# }