Dieker works in the area of Applied Probability, and his research is motivated in part by applications to computer networks and to business processes such as workforce management and service systems. His expertise includes stochastic processes, stochastic networks, and stochastic analysis of algorithms. He recently received a CAREER Award from the National Science Foundation and The Erlang Prize from the Applied Probability Society of INFORMS. He serves as an associate editor for Operations Research and Mathematics of Operations Research.