llnhlogit {bayesm} | R Documentation

## Evaluate Log Likelihood for non-homothetic Logit Model

### Description

`llmnp` evaluates log-likelihood for the Non-homothetic Logit model.

### Usage

    llnhlogit(theta, choice, lnprices, Xexpend)

### Arguments

`theta` | parameter vector (see details section)
`choice` | n x 1 vector of choice (1, ..., p)
`lnprices` | n x p array of log-prices
`Xexpend` | n x d array of vars predicting expenditure

### Details

Non-homothetic logit model with: ln(psi_i(U)) = alpha_i - e^{k_i}U

Structure of theta vector
alpha: (p x 1) vector of utility intercepts.
k: (p x 1) vector of utility rotation parms.
gamma: (k x 1) – expenditure variable coefs.
tau: (1 x 1) – logit scale parameter.

### Value

value of log-likelihood (sum of log prob of observed multinomial outcomes).

### Warning

This routine is a utility routine that does not check the input arguments for proper dimensions and type.

### Author(s)

Peter Rossi, Graduate School of Business, University of Chicago Peter.Rossi@ChicagoGsb.edu.

### References

For further discussion, see Bayesian Statistics and Marketing by Rossi, Allenby and McCulloch,Chapter 4.
http://gsbwww.uchicago.edu/fac/peter.rossi/research/bsm.html

### See Also

`simnhlogit`

### Examples

    ##
    ## Not run: ll=llnhlogit(theta,choice,lnprices,Xexpend)

[Package bayesm version 2.0-8 Index]