Employment Location Choice Model (ELCM)

Objective

The Employment Location Choice Model predicts the location choices of new or relocating jobs.

Algorithm

Jobs to be located by this model are those that were added by the EmploymentTransitionModel or predicted to move by the EmploymentRelocationModel. The model selects all those jobs with no location, and identifies all available, vacant nonresidential space within the simulation year. Since the choice sets are generally too large, normally random sampling of alternatives is used to construct plausible sized choice sets. It then uses a Multinomial Logit Model structure to generate location choice probabilities across the choice set for each locating job. The location probabilities are used with Monte Carlo Sampling to make a determination for each job regarding which of the available locations they will choose. Once a job has chosen a location, that location is committed to the job (like a lease or purchase contract) and the space becomes unavailable for any other locating jobs, until such time as the occupying job is predicted to move.

Configuration

OPUS path to model code

urbansim.models.employment_location_choice_model

Model Parameters

The configuration of the ELCM in the zone model system is summarized in the following table:

Element	Setting
Agent	Job
Location Set	Buildings - which are located on zones, so this is really a zone + building type location choice
Dependent Variable	Location of each job: building_id (zone and building_type)
Model Type	Multinomial Logit Model
Estimation Method	Maximum Likelihood
Submodels	Building Type - separate models are specified for groups of jobs by employment sector
Independent Variables	Attributes of buildings: Price, density, accessibility, zonal composition of households and employment

Data

The following tables are used by the Employment Location Choice Model in the zone-based version of UrbanSim.

Table Name	Brief Description
jobs	Jobs table with an inventory of employment
employment_sectors	Employment sectors, defined using NAICS or SIC classifications of industry
buildings	Buildings from which available non-residential sqft are evaluated for location
zones	Zones are used to compute density, social composition, and accessibility variables
travel_data	Skims from the travel model are used to compute accessibility variables

-- PaulWaddell - 07 Dec 2009