Two different frameworks have been developed to assess the potential effects of noise associated with offshore renewable energy developments on harbour porpoise populations: The Interim Population Consequences of Disturbance (iPCoD) and Disturbance Effects of Noise on the Harbour Porpoise Population in the North Sea (DEPONS). Although both models simulate population dynamics based on the birth and survival rates of individual animals, they model survival in a different way. iPCoD uses average survival rates derived from data from North Sea animals. In the DEPONS model, survival emerges from the individuals’ ability to continuously find food. In this report we compare the structure of the two models, and describe the data they require and the kinds of output they provide. We then identify key differences between the approaches and discuss how their outputs can be compared. SEE MORE