Oja's research focuses on 20th- and 21st-century American musical traditions. Her book, Making Music Modern: New York in the 1920s (2000), won the Lowens Book Award from the Society for American Music and an ASCAP-Deems Taylor Award. Other books include Copland and his World (co-edited with Judith Tick, 2005); Colin McPhee: Composer in Two Worlds; A Celebration of American Music: Words and Music in Honor of H. Wiley Hitchcock; and American Music Recordings: A Discography of 20th-Century U.S. Composers. She is completing a book provisionally titled Bernstein Meets Broadway: Collaborative Art in a Time of War (to be published by Oxford University Press). Oja was one of the directors of Harvard's Leonard Bernstein--Boston to Broadway, a conference and festival that took place in 2006, and she was co-director (with Anne Shreffler) of Crosscurrents: American and European Music in Interaction, 1900-2000, a conference at Harvard in the fall of 2008 and Munich the following spring. The proceedings of Crosscurrents will be published by The Boydell Press in 2012. She is a member of Harvard's Standing Committee of the History of American Civilization as well as the Steering Committee of the Charles Warren Center for American History. She is past-president of the Society for American Music.