TROMP: A PROBIT AND LOGIT MODEL

Availability: TROMP can be ordered from the ITS Systems Unit

Background: TROMP is the third in a series of computer programs that have been developed by researchers at the Institute of Transportation Studies to calibrate and predict with discrete choice models. The emphasis in these programs has been on providing as flexible a research tool as possible.

CHOMP, whose purpose was to make multinomial probit estimations possible, was the first of these packages. It was written in experimental form and later converted to a user-oriented version with an additional logit option. CONFID, the second program in the series is a data management program that can be used for prediction purposes and provides confidence intervals.

TROMP was developed to provide a more user-oriented, faster, and more accurate version of CHOMP and CONFID. TROMP also has Addition features were also incorporated into the TROMP model.

Description of Model: TROMP is a Trinomial probit computer package that has been developed to calibrate probit discrete choice models with two or three alternatives, and multinomial logit models with up to ten alternatives. The main advantage of TROMP are that it is fast, can consider nonlinear specifications, and uses exact probit probabilities and analytical derivatives. It also has the capability to deal with repeated observations and choice-based samples. TROMP also features various prediction methods and has the ability to produce confidence intervals for the predictions.

System requirements: TROMP is a DOS program that runs on a PC.

User's Guide: "TROMP USER'S MANUAL: Calibration, Prediction, Confidence Intervals with Trinomial Probit, Binary Probit, and Multinomial Lodgit", an ITS research report, UCB-ITS-RR-82-4, 1982, by Jurg M. Sparmann and Carlos Daganzo.

Support: No support is provided for this model.

Contact Information: To order TROMP, please contact Lannon Leiman at the ITS Systems Unit:
Phone (510) 642- 1008
Email: lannon@uclink.berkeley.edu