Purpose - The main objective of this paper is to illustrate the prospects but also the limits of quantifying external benefits of urban and real estate development projects using the method event study. Another objective is the comprehensible derivation of an appropriate controlling system in step with actual practice.Design/methodology/approach - We first provide a general theoretical background by determining the factors for urban and real estate projects and by highlighting the increasing importance of cooperative models. The presentation of the event study builds the methodological framework for the quantification of external benefits. Further, we develop a systemization of external benefits using a set of four dimensions: targets, stakeholder, space and time. Based on this, the project example Le Quartier Central (Duesseldorf) then serves both, clarifying the achieved systematization and applying the method event study.Findings - Existing measurement and controlling instruments are only of limited use for the striven extensive analysis of external benefits in a management and controlling process. A combination or enlargement of the existing instruments (e.g. CBA or event study) towards an integrated controlling approach seems to be necessary at this stage. Research Implications - Further research should focus on the application of suitable methods to measure or pricing external benefits within a controlling framework. Practical implication - The intended outcome of this paper is an increasing awareness of the importance of analysing respectively measuring external benefits of urban development projects followed by an increasing application of controlling methods in the field of urban planning.Originality/value - The results of this paper are of high value for practitioners in several fields of urban planning, e.g. municipal planners receive methodological support in all stages of a project life cycle to assure sustainable urban development.