NYC-WTC_000187725

NYC 9/11 Public Portal Document

34 uncorrelated in the idiosyncratic utilities households attach to them, then c = 1. Otherwise, if c = 0, dwellings in the same (j,k,m) are identical and function as perfect substitutes. The logit model given by (8) has the property that alternative residential choices are gross substitutes (i.e., as the rent of choice (j,k,m) increases, keeping all- else constant, the probability of choosing (j,k,m) does not increase and the probability of choosing every (r,x,s) not equal to (j,k,m) does not decrease). The model was set up under the presumption that each household i had a single worker. To deal with multiple working members, in order to express the relationship on a per worker basis, the budget constraint is adjusted so that it represents a budget per working h* member in the household, assuming that working members share equally in income, rent and shopping expenditures. Hence,

(2') 1 n

0j is the number of household residents of zone j divided by the number of workers resident in zone j. If y^ is measured as the income of the worker, then the function is a budget constraint prorated to each working member in a household. Dividing (2*) y i through by 0j, it is put in a form similar to (2), except that the values of income and commuting cost in (2) have been divided by 0^. Hence, i I (2”) 1 n

where y^j = y^/Oj and Previously stated equations are readusted to reflect^these ^definitions.^

We now turn to the formulation of the equilibrium system of equations of the model. Suppose that is the number of workers employed in zone i. Then, at equilibrium, the number of households choosing housing type k in residential zone j should equal the number of occupied dwellings of type k in residential zone j . This is expressed for each (j,k) by

for each (j.k) (9) j. m

The data does not allow us to model the travel of each working member in a household. Also, the Census data gives the value of 6 by place of residence j, not by place of work i.

CITY_21MC100_006662265

NYC-WTC_000187765