Instead of building separate geospatial information systems (GIS) for different departments, many local governments develop single systems to serve all departments. However, creating an enterprise GIS (E-GIS) requires significant up-front costs, and many city and county managers balk at the investment required, in part, because they cannot justify the expense.

To resolve that sticking point, the GIS Forum for the Washington-based Public Technology Institute (PTI) has begun building a model for calculating return on investment (ROI) for E-GIS. It incorporates the costs of major components and proposes possible benefits that local managers can include in their calculations, such as:

Higher census counts. Geospatial data are critical in census-taking operations, which help determine federal and state funding to local governments. Detailed E-GIS information can increase population counts by 5 percent or more. If a jurisdiction of 100,000 receives $200 per capita in federal and state grants, a 5 percent census increase could result in an additional $1 million annually.

Improved property tax collection. Components of E-GIS can be used to find properties omitted from the tax rolls and identify improvements not yet included in assessed value. For many, that can lead to at least a 1 percent increase in property taxes, which, when calculated against annual property tax revenues, can increase revenue by hundreds of thousands of dollars.

Quicker emergency dispatch and crime analysis. Accurate address data along with state-of-the-art emergency dispatch applications can cut average ambulance response times by one minute or more. In cases of sudden cardiac arrest, that faster response can reduce fatalities by 10 percent.

Crime analysis using E-GIS that leads to effective police tactics can significantly reduce violent crime. For example, New York City's murder rate declined from a peak of 2,262 in 1990 to 596 in 2006 with the assistance of the CompStat crime analysis program, which includes GIS. For the purpose of calculating ROI, it is not unreasonable to estimate $1 million per death avoided, which would include the social, economic and tax value of the life lost, the cost of the police investigation and trial, and the reduction of economic development activity because of violent crime.

Field force automation. E-GIS data with global positioning systems, mobile computers and wireless communications can increase the productivity of inspectors, social service workers and service crews by 25 percent or more, allowing them to address other important assignments, which can and should be quantified as a significant benefit.

The full E-GIS ROI model includes many more benefits and focuses especially on the uses of GIS that increase revenue collection and reduce financial losses. To date, the model suggests that jurisdictions can pay back the expense of E-GIS within five years through financial gains alone. Combined with other benefits that have been converted into their equivalent dollar value, ROI soars and can demonstrate a $4 return for every $1 invested over 10 years.

For more information about the GIS ROI Model, contact Dale Bowen, PTI GIS Forum manager at (202) 626-2456 or dbowen@pti.org.

The author is the former GIS director for New York City and is currently a senior associate for McLean, Va.-based Booz Allen Hamilton.