In 2003, an index seemed like a good idea for Long Island. It would report on how the region was doing, compare it with other suburban areas and measure progress. What emerged — after consultations with business, civic, and political leaders — was the Long Island Index.

After 15 years, the role of the regional index passes this month from the Long Island Index to nextLI, a new research arm of Newsday’s editorial board. It’s an appropriate time to reflect on a formula that led Long Island to start thinking and acting regionally.

The Index has provided data on Long Island — including trends over time and comparisons with similar regions — to raise awareness of key issues, encourage regional thinking and inspire Long Islanders to work together. Providing that data has been the mission of the Index, which yielded a crucial formula for Long Island’s future progress.

That formula has four components: objective data that underscore a broader context for Long Island; a focus on regional assets and how to leverage them; generation of new ways to cooperate; and progress realized through advocacy and engagement.

The data are the foundation. The findings show how Long Island stands, and whether it is making headway. Interactive maps make the data accessible, and opinion surveys have added another layer of information. Most important, the surveys have revealed that Long Islanders are more willing to embrace change than many political leaders thought possible. For instance, 68 percent of Long Islanders support changing zoning laws to make it easier to install a rental apartment in a single-family home.

Our regional assets give us enormous potential. They include world-class research institutions, a public transit system with 124 rail stations, a renowned quality of life and natural beauty.

Developing ways to work together to use those assets is essential to thinking regionally because Long Island has 665 government entities providing essential services — a major obstacle to our competitiveness. We compete economically as a region, yet decisions that affect our competitiveness are made locally and spread across hundreds of jurisdictions.

The Index has encouraged Long Island leaders from different sectors to work together. Its advisory committee has been a model of collaboration, driving interaction among the region’s influencers and communities.

That collaboration, combined with the data and assets available, led to other models of cooperation and partnership. The Energeia Partnership, created and managed by Molloy College, for instance, uses the Index as core curriculum to educate young Long Island leaders. The Right Track for Long Island Coalition was created to champion the LIRR’s third track to help relieve the bottleneck on the 9.8-mile stretch of the Main Line between Floral Park and Hicksville. The Metropolitan Transportation Authority’s approval of the third track, with the leadership of Gov. Andrew M. Cuomo and the coalition, proved that the seemingly impossible can be achieved when we work together.

The challenge now is to implement that approach more broadly to find ways to propel progress, which is needed on many issues. Long Island is still suffering a brain drain as a shocking number of young residents say they plan to leave because of a lack of affordable housing. Segregation in schools and housing must be eliminated. Economic opportunities in biotechnology and related fields must be enhanced. And we still have those 665 government entities.

We have extraordinary potential. nextLI will provide the essential data to understand where Long Island stands as a region and where it needs to go. But the challenge of cooperation and progress falls to all of us. We are all part of the solution.