You might be simply struggling with some cognitive hurdle here, I don't know what it is, and it's hard for me to help you.
Maybe try to research the city of Barcelona, its topology, the available space for construction, the process of developing high-rise buildings, and then try to ask yourself what steps need to be taken to build 100k new flats in the city?
Consider the infrastructure, the cost, the timeframe, steps needed to ensure quality, and make sure that it doesn't become unliveable like american downtowns, compensation to the current residents whose flats would have to be demolished, damage to the city's character...
Then you could maybe think about what happens when rent prices drop, and whether a decrease in apartment prices that follow would have some effect on the number of mortgage defaults.
Maybe consider the political support you'd need for such a development and how you'd get it from the existing residents?
Finally try to do some napkin math and figure out how quickly these new units would be bought up as vacation houses by the rest of Europe and the rest of Spain moving from smaller towns to the newly available stock in the city. For bonus points you could try to estimate how much new housing was built in Barcelona in the last 20 years.
Maybe that'll help. I'm really not sure what you mean by "identification strategies", but thanks for all your research about just letting developers build denser housing. I'm sure if they just listened to your simple advice, the problem would have been solved long ago. NYC and SF are known for their affordable and high quality rentals.
NYC and SF under build severely. Have a look at the chart of their building versus Tokyo, the only place that actually has kept a lid on rental inflation.
> You might be simply struggling with some cognitive hurdle here
Arrogance is thinking your myopic macro model has the power to fix every housing price crisis in the world. While ignoring every important factor but one.
Maybe try to research the city of Barcelona, its topology, the available space for construction, the process of developing high-rise buildings, and then try to ask yourself what steps need to be taken to build 100k new flats in the city?
Consider the infrastructure, the cost, the timeframe, steps needed to ensure quality, and make sure that it doesn't become unliveable like american downtowns, compensation to the current residents whose flats would have to be demolished, damage to the city's character...
Then you could maybe think about what happens when rent prices drop, and whether a decrease in apartment prices that follow would have some effect on the number of mortgage defaults.
Maybe consider the political support you'd need for such a development and how you'd get it from the existing residents?
Finally try to do some napkin math and figure out how quickly these new units would be bought up as vacation houses by the rest of Europe and the rest of Spain moving from smaller towns to the newly available stock in the city. For bonus points you could try to estimate how much new housing was built in Barcelona in the last 20 years.
Maybe that'll help. I'm really not sure what you mean by "identification strategies", but thanks for all your research about just letting developers build denser housing. I'm sure if they just listened to your simple advice, the problem would have been solved long ago. NYC and SF are known for their affordable and high quality rentals.