Collision and displacement/barrier impacts for seabirds interacting with offshore wind farms (OWFs) are currently assessed using separate modelling methods. This means collision mortality is estimated separately from displacement and barrier effects, and the effect sizes are subsequently combined. However, there is concern with this approach because the parameters used in both assessments are not equivalent, making integration subject to error. Secondly, there is concern about double counting of mortalities: an individual seabird is potentially vulnerable to displacement and collision, yet it cannot be vulnerable to both simultaneously. Accordingly, the objective of this project was to develop a framework within which collision, displacement and barrier effects can be aggregated into a single overall assessment of combined impacts in a way that is internally consistent, scientifically defensible, and practically useful.