financial data several years down the road. He may notice a sudden rise in sales-tax revenue during the latter part of 2001, but if the warehouse lacks additional information, such as news reports mentioning President Bush's tax relief package with its billions of dollars in rebates that were pumped into the economy, the analyst may falsely assume the rise in receipts were due to some other factors. The result could be bad fiscal policy based on incomplete information.

Entering the Enterprise Era

An enterprise data warehouse starts with a strategy for integrating data from various agency systems, consolidating descriptive information into a system that is accessible to each state department, according to Dan Paolini, New Jersey's director of Data Management Services. The result is less wasteful duplication of information.

"We found there are certain types of data that have more value than others in an enterprise data warehouse," said Paolini. "So we identified the data that had the most immediate interest for all agencies."

That turned out to be a finance, payroll and personnel data warehouse that each agency can access and analyze. But before the warehouse can operate on such a scale, the state has had to come up with a logical data model and framework so that agencies provide information that is consistent and accurate, whether it includes people, places or organizations; is relevant to a broad group of agencies, such as human services or criminal justice; or is specific to an individual agency and is not shared or integrated.

Cleaning data so that it can be integrated and accessed in a logical way is a major part of any government warehouse project, according Paolini. "But that's minimal compared to the organizational problem of getting agencies to see the value of sharing data," he said. "Fortunately, the drive for electronic government within the state has helped push down the barriers in terms of data sharing."

So far, New Jersey has spent about $700,000 on its warehouse project for consulting, data warehouse tools and other needs. Plans are already under way to broaden the use of the warehouse into other areas, including criminal justice.

In Michigan, where the state is building an enterprise data warehouse with its business partner, Bull, the issue of merging disparate data from several agencies into a single mainframe stands out as a particular challenge, according to state CIO George Boersma. With the state spending nearly $4 million on warehouse projects, Boersma wants to be sure the effort generates the right kind of payback. One concern he has is making sure the agencies are relying on the warehouse for analytical, not just transactional, purposes.

So far, the strategy is working. The warehouse supports the state's Medicaid program for fraud and abuse, child support and the state Treasury for financial auditing. All these projects are generating a return on investment through cost savings and new revenue.

Join the Fray

A number of cities have also begun using data warehouses, but with a twist. In New York City, the development of a massive spatial data warehouse is under way. Address-based information plays a crucial role in municipal government, according to Alan Leidner, the city's GIS coordinator. The problem in New York, as New Jersey has discovered, is that different departments use different formats for the same kind of information. The result is inconsistency.

"The use of GIS in local government hinges on orienting all geo data to a common set of standards," explained Leidner. "We are working to get all this data to meet base map standards, identify the data most commonly used by as many departments as possible and centrally locate it for distribution back to the agencies."

The city is working with Oracle to develop a common platform for its spatial warehouse.