Mary Riddel completed her degree in Agricultural and Resource Economics at Colorado State University in 1998. She also holds an MS degree in statistics from that institution. From 1997 through 1998, she worked as the senior economist at the University of California Santa Barbara for the Economic Forecast Project. She came to UNLV as an assistant professor in 1999 and was advanced to full professor in 2011. She served as associate director of The Center for Business and Economics Research (CBER) from 1999-2005, then as interim Director of CBER in 2009. In 2010, she was designated as a Beam Research Scholar by the Lee Business School (LBS). She is currently chair of the economics department.

Riddel has published in a broad range of fields including statistics, environmental & behavioral economics, housing, and natural resource law. She has studied the public’s support for the proposed Yucca Mountain Nuclear Waste Repository, improving water quality, biodiversity, and open space programs. Riddel's recent research explores the economics of risk and uncertainty from a behavioral perspective. She is working on models that will help researchers understand why people engage in risky activities and design better ways to communicate health and safety risks to the public. Her publications have appeared in the Journal of Environmental Economics and Management, Risk Analysis, Journal of Risk and Uncertainty, Journal of Statistical Computation and Simulation, Land Economics, The Journal of Housing Economics and the Natural Resources Journal, among others.

She enjoys teaching a broad range of undergraduate and graduate statistics courses. She currently teaches graduate mathematical economics, econometrics, as well as a graduate seminar in behavioral economics. In the past, she has taught undergraduate statistics for business as well as graduate and undergraduate courses in environmental and resource economics.

Riddel has worked on consulting projects for businesses locally and nationally on an ongoing basis since she came to UNLV. She has consulted on the economic impact of solar and other renewable technologies, the economic impact of the proposed high–speed train to Las Vegas, and the economic impact of the proposed Yucca Mountain Nuclear Waste Storage Facility. Her recent consulting work addresses how people make decisions to consume risky products.