[mhays]

Population growth is certainly a good clue! But it's not definitive, and volumes can vary tremendously within that metric.

Some of that is filling in past overbuilding. There might be very little construction until things tighten a bit.

Then you get a lag effect. If offices are 20% vacant, construction volumes might not really gain steam until it's 15% or 10%.

Cities also invest at very different levels. Some electorates enthusiastically support big infrastructure programs and others are more reticent.

Another factor is that a large percentage of all work is renovations and buildouts, not new construction. For example in richer areas, housing tends to be renovated more often, partially because the housing value will tend to rise more than the renovation cost.