are often used in media mentions of the region. These include the Office of Management and Budget's Pittsburgh, PA Metropolitan Statistical Area (MSA) and Pittsburgh-New Castle-Weirton, PA-OH-WV Combined Statistical Area (CSA). The Nielsen Corporation's Pittsburgh Designated Market Area (DMA) is another commonly used formal definition of the region. There are nineteen counties included in at least one of these definitions and their combined population was over 2.9 million in 2016. Economy Historically, Pittsburgh has been grouped in the "rust belt"; however, reflective of the rebound of the region within the last generation, the metro area has been included as a part of the "Great Lakes Basin" gaining representation in the Great Lakes Metro Chamber Coalition. Pittsburgh's association with the Great Lakes region is due in part to its economic, demographic and commuter connections to Great Lakes cities like Cleveland, Erie, Toledo and even Detroit. Christopher Briem, an economist at the University of Pittsburgh's University Center for Social and Urban Research, has argued that southwestern Pennsylvania is "far more interconnected" with northeastern Ohio than it is with the eastern half of Pennsylvania, and that the industries of Pittsburgh are primarily linked to Ohioan cities such as Youngstown, Akron, and Cleveland, not to Pennsylvanian cities such as Allentown, Scranton, or Philadelphia. He notes that, conversely, the population centers of northeastern Ohio are primarily connected with Pittsburgh and only secondarily connected to the state capital of Columbus. Briem argues that "In so many ways the state boundaries we think of as important are no more than lines on a map." In recognizing their economic interdependence, Briem coined the term "Cleveburgh" to refer collectively to the cities of Cleveland and Pittsburgh, along with the smaller towns dotting the corridor of I-76 between the cities. Robert Lang and Arthur Nelson of the Metropolitan Institute at Virginia Tech also identify the region between Cleveland and Pittsburgh as being an interconnected "megapolitan area" and refer to it as the "Steel Corridor". Education The largest school district in the area is the Pittsburgh Public Schools, with the school districts of Allegheny County also boasting large student bodies. Many private schools also serve the core county of Allegheny. More public districts are found throughout Beaver, Westmoreland, and Washington counties, as well as private schools in each county. Several area colleges and universities serve the region. Pittsburgh itself is home to many colleges, universities and research facilities, the most well-known