Oja's research focuses on 20th- and 21st-century American musical traditions, and her current project is tentatively titled “Black Virtuosos and Civil Rights: Performing Racial Desegregation after World War II.” Her most recent book, Bernstein Meets Broadway: Collaborative Art in a Time of War, was published by Oxford University Press in 2014.
Crosscurrents: American and European Music in Interaction, 1900-2000, edited together with Felix Meyer, Wolfgang Rathert, and Anne Shreffler, appeared from The Boydell Press that same year, as did Music and Musical Composition at the American Academy in Rome, edited by Martin Brody (to which she contributed two chapters). Oja’s Making Music Modern: New York in the 1920swon the Lowens Book Award from the Society for American Music. Other books include Copland and his World (co-edited with Judith Tick); 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 has won three ASCAP-Deems Taylor Awards.