biogeme 2.6a [Mon Apr 17 15:32:48 CEST 2017]

Michel Bierlaire, EPFL

This file has automatically been generated.

Tue Apr 18 19:12:10 2017

Tip: click on the columns headers to sort a table [Credits]

Example of a mixture of logit model with panel data, for a transportation mode choice with 3 alternatives:
- Train
- Car
- Swissmetro, an hypothetical high-speed train
We introduce error components with alternative specific variance.
This example shows that constraining one of the sigma to zero does *not* lead to the same model. It is not a proper normalization, as discussed by Walker (2001, Appendix C).
The estimates for the logit model are used as starting points for the estimation
Model: Mixed Logit for panel data
Number of Hess-Train draws: 500
Number of estimated parameters: 6
Number of observations: 6768
Number of individuals: 752
Null log likelihood: -6964.663
Init log likelihood: -3840.088
Final log likelihood: -3837.739
Likelihood ratio test: 6253.847
Rho-square: 0.449
Adjusted rho-square: 0.448
Final gradient norm: +4.594e-05
Diagnostic: Normal termination. Obj: 6.05545e-06 Const: 6.05545e-06
Iterations: 12
Run time: 02:22
Variance-covariance: from finite difference hessian
Sample file: ../swissmetro.dat

Utility parameters

Name Value Std err t-testp-valueRobust Std err Robust t-testp-value
ASC_CAR-1.030.197-5.240.000.646-1.600.11*
ASC_SM0.00fixed
ASC_TRAIN-2.190.234-9.370.000.482-4.540.00
B_COST-2.850.171-16.690.000.424-6.730.00
B_TIME-2.900.146-19.850.000.590-4.920.00
SIGMA_CAR4.080.30413.420.001.183.460.00
SIGMA_TRAIN3.550.22215.990.000.27113.100.00
ZERO0.00fixed

Utility functions

IdNameAvailabilitySpecification
1A1_TRAINTRAIN_AV_SPASC_TRAIN * one + B_TIME * TRAIN_TT_SCALED + B_COST * TRAIN_COST_SCALED + ZERO [ SIGMA_TRAIN ] * one
2A2_SMSM_AVASC_SM * one + B_TIME * SM_TT_SCALED + B_COST * SM_COST_SCALED
3A3_CarCAR_AV_SPASC_CAR * one + B_TIME * CAR_TT_SCALED + B_COST * CAR_CO_SCALED + ZERO [ SIGMA_CAR ] * one

Variance of random coefficients

NameValueStd errt-testRobust Std errRobust t-test
ZERO_SIGMA_CAR16.72.496.71
ZERO_SIGMA_TRAIN12.61.587.99

Correlation of coefficients

Coefficient1 Coefficient2CovarianceCorrelationt-testp-valueRob. cov.Rob. corr.Rob. t-testp-value
B_COST B_TIME0.01180.4740.320.75 *0.02960.1180.080.94 *
SIGMA_CAR SIGMA_TRAIN0.006380.09441.480.14 *0.04030.1260.450.65 *
ASC_TRAIN B_TIME-0.0105-0.3072.290.02 -0.226-0.7930.700.48 *
ASC_TRAIN B_COST0.0009720.02442.310.02 0.06490.3181.250.21 *
ASC_CAR B_TIME0.0003310.01157.650.00 -0.146-0.3821.820.07 *
ASC_CAR ASC_TRAIN0.005040.1094.000.00 0.2060.6612.370.02
ASC_CAR SIGMA_CAR-0.0132-0.220-12.880.00 -0.660-0.865-2.890.00
ASC_CAR B_COST0.01180.3518.610.00 0.1860.6803.830.00
ASC_TRAIN SIGMA_CAR0.007930.112-17.310.00 -0.205-0.361-4.390.00
B_COST SIGMA_CAR-0.0296-0.569-16.300.00 -0.325-0.649-4.650.00
B_TIME SIGMA_CAR-0.0295-0.662-16.800.00 0.02270.0325-5.360.00
ASC_CAR SIGMA_TRAIN-0.00367-0.0838-14.830.00 -0.0200-0.115-6.300.00
B_TIME SIGMA_TRAIN-0.00365-0.112-23.110.00 -0.0348-0.217-9.210.00
ASC_TRAIN SIGMA_TRAIN-0.0300-0.577-14.180.00 -0.0219-0.167-9.710.00
B_COST SIGMA_TRAIN-0.00411-0.108-21.740.00 -0.0242-0.211-11.660.00

Smallest singular value of the hessian: 4.75116