alsos {DAMisc}R Documentation

Alternating Least Squares Optimal Scaling

Description

Estimates the Alternating Least Squares Optimal Scaling (ALSOS) solution for qualitative variables.

Usage

alsos(
  os_form,
  raw_form = ~1,
  data,
  scale_dv = FALSE,
  maxit = 30,
  level = 2,
  process = 1,
  starts = NULL,
  ...
)

Arguments

os_form

A two-sided formula including the independent variables to be scaled on the left-hand side. Optionally, the dependent variable can also be scaled.

raw_form

A right-sided formula with covariates that will not be scaled.

data

A data frame.

scale_dv

Logical indicating whether the dependent variable should be optimally scaled.

maxit

Maximum number of iterations of the optimal scaling algorithm.

level

Measurement level of the dependent variable 1=Nominal, 2=Ordinal

process

Nature of the measurement process: 1=discrete, 2=continuous. Basically identifies whether tied observations will continue to be tied in the optimally scaled variale (1) or whether the algorithm can untie the points (2) subject to the overall measurement constraints in the model.

starts

Optional starting values for the optimal scaling algorithm.

...

Other arguments to be passed down to lm.

Value

A list with the following elements:

result

The result of the optimal scaling process

data

The original data frame with additional columns adding the optimally scaled DV

iterations

The iteration history of the algorithm

form

Original formula

Author(s)

Dave Armstrong and Bill Jacoby

References

Jacoby, William G. 1999. ‘Levels of Measurement and Political Research: An Optimistic View’ American Journal of Political Science 43(1): 271-301.

Young, Forrest. 1981. ‘Quantitative Analysis of Qualitative Data’ Psychometrika, 46: 357-388.

Young, Forrest, Jan de Leeuw and Yoshio Takane. 1976. ‘Regression with Qualitative and Quantitative Variables: An Alternating Least Squares Method with Optimal Scaling Features’ Psychometrika, 41:502-529.


[Package DAMisc version 1.7.2 Index]