What are the effects of rent controls?

I will bite. Not unlike an increase in minimum wage, it increases competition at the margin among landlords, which increases amenities, and encourages families and economic activity. It needs to also be accompanied by enforcement of landlord citations as well as empty housing penalties though in order to have its full effect of reversing the trend of out of state management of private residential property and encourages self-ownership over time and better landlords. The empty housing penalties are because the landlords primary use of the properties is capital and so an empty unit is often more profitable in value than the cost of it sitting empty. Laws need to tip the scale to increase supply of housing and force their hands to release it back to people who can take on personal responsibility of the unit, whether that be a next door landlord or ideally a rent to own tenant or owner living there.