It really shouldn't require a study. Unfortunately, in the wild many people have observed a correlation between rising rents and new construction. If an area has become more desirable to live in, for some exogenous reason, then rents are likely to increase while new construction is likely to also occur. This doesn't mean that the new construction is driving the rent increases, it's actually likely that it's the other way around, but they do happen at roughly the same time. In fact, it should be easy to imagine that if the exogenous demand increase occurred and new housing was prohibited how rent increases might be even larger than they otherwise would be.