It's also easy to be struck by just how many ‘waves’ there are, and how diverse their causes can be. Non-economic waves Many of these waves come from causes that are in some sense outside the economic system. [3] Demographic forces are perhaps the best-known of these.
Because these forces play out over long periods, they are usually thought of as being outside the system, though of course policy can affect demography to some extent. The rise of China and its wave of urbanisation is a good example where policy and underlying demography have both mattered. With that urbanisation has come a lot of housing and infrastructure construction.