Cities are a key driver of national prosperity, producing on average more than half of GDP, even in developing countries. They do this by concentrating activity, resources and knowledge to exploit agglomeration effects and economies of scale. These effects are not always present however and can be reduced where cities to not achieve the necessary levels of densification and infrastructure services provision. This paper looks at the journey from urban productivity outcomes to economic growth, the constraints on the growth narrative as well as recommending areas for further research.