biogeme 2.5 [Dim 19 jui 2016 17:58:58 CEST]

Michel Bierlaire, EPFL

This file has automatically been generated.

Wed Jul 6 20:17:01 2016

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: -3841.012
Final log likelihood: -3839.008
Likelihood ratio test: 6251.311
Rho-square: 0.449
Adjusted rho-square: 0.448
Final gradient norm: +3.094e-05
Diagnostic: Normal termination. Obj: 6.05545e-06 Const: 6.05545e-06
Iterations: 12
Run time: 03:20
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-0.9060.193-4.690.000.523-1.730.08*
ASC_SM0.00fixed
ASC_TRAIN-1.930.223-8.670.000.356-5.430.00
B_COST-2.770.168-16.510.000.330-8.380.00
B_TIME-3.040.144-21.090.000.567-5.370.00
SIGMA_CAR4.140.26615.560.000.6366.510.00
SIGMA_TRAIN3.370.19317.460.000.29811.320.00
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_CARinf2.20inf
ZERO_SIGMA_TRAIN11.41.308.73

Correlation of coefficients

Coefficient1 Coefficient2CovarianceCorrelationt-testp-valueRob. cov.Rob. corr.Rob. t-testp-value
B_COST B_TIME0.01230.5081.770.08 *0.04410.2360.470.64 *
SIGMA_CAR SIGMA_TRAIN0.006750.1322.500.01 -0.0480-0.2541.000.32 *
ASC_TRAIN B_TIME-0.0102-0.3183.690.00 -0.145-0.7211.290.20 *
ASC_TRAIN B_COST-0.00380-0.1022.860.00 0.01360.1151.830.07 *
ASC_CAR ASC_TRAIN0.001620.03773.540.00 0.09210.4952.200.03
ASC_CAR B_TIME0.002600.09359.290.00 -0.117-0.3932.350.02
ASC_CAR B_COST0.01180.3649.100.00 0.07500.4343.860.00
ASC_CAR SIGMA_CAR-0.0176-0.343-13.330.00 -0.278-0.835-4.540.00
ASC_TRAIN SIGMA_CAR0.009740.164-19.110.00 -0.0320-0.142-7.870.00
B_TIME SIGMA_TRAIN-0.00514-0.185-24.530.00 -0.115-0.684-8.010.00
B_COST SIGMA_CAR-0.0279-0.626-17.560.00 -0.0929-0.442-8.260.00
B_TIME SIGMA_CAR-0.0256-0.667-19.010.00 -0.00831-0.0230-8.330.00
ASC_CAR SIGMA_TRAIN0.003330.0895-16.420.00 0.08410.540-9.710.00
ASC_TRAIN SIGMA_TRAIN-0.0245-0.569-14.390.00 0.02820.266-13.310.00
B_COST SIGMA_TRAIN-0.00197-0.0608-23.320.00 -0.00269-0.0274-13.620.00

Smallest singular value of the hessian: 4.76873