Prof. Shaddick's research interests include the theory and application of Bayesian hierarchical models and spatio-temporal modelling in a number of fields including epidemiology, environmental modelling, disease progression in rheumatology. He is also actively engaged in research with the power industry, using big data to model demand profiles, forecasting demands and identifing customer profiles, and the use of data reduction techniques. Of particular interest are computational techniques that allow the implementation of complex statistical models to real-life applications where the scope over both space and time may be very large.

He is a co-author of Spatio-Temporal Methods in Environmental Epidemiology and the Oxford Handbook of Epidemiology for Clinicians, which was Highly Commended in the Basis of Medicine Category, BMA Book Awards 2013.