About 75 percent of high school students in the United States graduate on time, but those who never get a diploma often earn less, resulting in lost economic activity for the country at large, U.S. News reports. How to boost the graduation rate? Take a holistic approach to engaging and empowering students, involving a range of community organizations and resources in addition to schools, says Elaine Wynn, chairman of Communities In Schools, a national nonprofit dedicated to preventing dropouts that operates in more than 3,400 schools. Wynn, a member of the board of directors of luxury hotel and casino developer Wynn Resorts, recently spoke with U.S. News about how the CIS model works and what legislators can do to address the dropout rate…