<p>A central component of the New Jersey: Link to the 21st Century project is the calibration of TRANUS, a land use-transportation model, for use in the study of northern New Jersey. The model will be used to forecast the impact of transportation investments on economic activity in the study area. Within TRANUS, the distribution of population within the region will be a function of basic (e.g., manufacturing) economic activity, which will be exogenous to the model. Service employment (employment in industries that serve the local residents, such as grocery stores) will then be a function of population. Two multipliers are required ? one which relates population to employment and one which relates service employment to population. These relationships are expressed as: P = … E ? … = P/E ES = ? P ? ? = ES/P Where: P is the population, E is the total employment, ES is the service employment, … is the population to employment multiplier, and ? is the employment multiplier. These equations express the concept that employment in basic economic sectors results in increased population which in turn increases service employment. Since … is just the ratio of total population to total employment, it is very easy to calculate. The calculation of ?, on the other hand, is more involved since it requires a determination of service employment. This paper describes the development of the service employment to population multiplier for the study area.</p>