The public realm has significant impacts on a society’s welfare, ranging from citizens’ well-being and satisfaction with life to economic activity and its productivity. Yet, we know very little about what aspects of the public realm bring most value to society. That is, the complex interplay between the different elements and actors shaping the public realm make it very difficult to place a value on public realm improvements. Consequently, decision-making can be poor and not well informed. This research will initiate the development of a Public Realm Economic appraisal Toolkit for Transforming Investments (PRETTI) to better inform and support policy decision-making in the field of urban realm. A sound and operational analytical and theoretical framework, combined with a solid evidence-base, are needed to advance optimal public intervention in the urban realm. PRETTI will lay out the necessary foundations that enable public authorities to appraise public realm schemes and make more informed decisions.