The city is constantly changing. New buildings are built, new infrastructure replaces old infrastructure, and the city grows with the addition of new areas. This study investigates the impact of new construction projects on the socioeconomic background and affordability of residents in Stockholm, Sweden. Using the difference-in-difference methodology, the authors analyse data from several construction projects in the city from 2009 to 2014. The results suggest a limited effect on the proportion of residents with higher education and young people, that is, no gentrification effect, but a positive effect on income and affordability. However, this could lead to gentrification and displacement over time. This research sheds light on the potential outcomes of urban development and highlights the need for effective policies to ensure sustainable and equitable growth in Stockholm.