James Warden, Finance and Commerce -- Minnesota and other states need to abandon conventional economic development strategies and instead zero in on sectors in which they have a competitive advantage and an established industry, speakers said Monday during a conference at the University of Minnesota’s Humphrey School of Public Affairs. A cluster approach brings focus to economic development efforts that are often disconnected from the realities on the ground, said Michael Porter, a Harvard Business School professor who led the cluster mapping effort for the U.S. Economic Development Association. States sometimes offer training for jobs that aren’t available or they use incentives to bring in plants that don’t have any reason to stay once those incentives expire. By contrast, targeting clusters allows regions to put their efforts in the places where they’re most likely to have success. In Boston, for example, officials focused on a biopharmaceuticals cluster. They don’t try to lure new plants to the area unless they make sense as part of that cluster. The result is an economy booming from what Porter called “a cluster of clusters.”