A misspecification test for logit based route choice models

- We show how White's information matrix test can be applied to route choice models.
- Results for path-based and link-based (recursive logit) models.
- Comparison of information matrix and IIA and McFadden-Train Lagrange multiplier tests.
- Monte Carlo experiment results assess the size and power of the tests.
- Both path-based and link-based models are strongly rejected when applied to real data.

The multinomial logit (MNL) model is often used for analyzing route choices in real networks in spite of the fact that path utilities are believed to be correlated. Yet, statistical tests for model misspecification are rarely used. This paper shows how the information matrix test for model misspecification proposed by White (1982) can be applied to test path-based and link-based MNL route choice models.We present a Monte Carlo experiment using simulated data to assess the size and the power of the test and to compare its performance with the IIA (Hausman and McFadden, 1984) and McFadden-Train Lagrange multiplier (McFadden and Train, 2000) tests. Moreover, we test models estimated on real data and they are all rejected. Attributes correcting for correlation (path size and link size) improve model fit but do not affect the outcome of the test.