Quantifying Problems Is Crucial

Quantifying problems is important.
Does an outflow of population necessarily lead to a drop in purchasing power? A deeper analysis requires examining multiple factors. Who is leaving? The wealthy or the poor? If poor residents are continuously leaving while wealthy ones are continuously moving in, and the city's size isn't expanding, does purchasing power per unit of land rise or fall? Therefore, it's the movement of those with purchasing power that warrants tracking.
The movements of groups without purchasing power are irrelevant to prices.