[3] She completed her Ph.D. in 2007 at Southern Illinois University; her dissertation, Labelings of Directed Graphs, was supervised by Walter D.
Beyond mathematics, her teaching at Southwestern has included a freshman seminar on television game shows.
[5] Marr is an advocate of inquiry-based learning in mathematics, a style of teaching through student research rather than through presentation of packaged solutions that is closely related to the Moore method.
She was one of the founding officers of the inquiry-based learning special interest group of the Mathematical Association of America, which was established in 2016.
[9] She spoke about magic graph labelings as an invited speaker at the Midwest Conference on Combinatorics, Cryptography, and Computing in 2011.