Table [ ]. Source: Balke and Gordon ; NBER Macrohistory Database
If we compare the reduction of investment in equipment in the fourth quarter of 1929 from its third-quarter level to the same reduction in the value of refined copper shipments, it becomes clear that the reduction in the latter constitutes 15.5% of the total reduction in investment in equipment. And if we consult one more time Fig. [ ] showing the dynamics of refined copper shipments and price, we will notice that the reduction in the value of copper shipments in the fourth quarter was caused entirely by a rapid drop in shipments. Such a drop is difficult to explain by something other than a sudden stoppage of a large number of projects. Moreover, the fact that the reduction in the refined copper shipments constitutes such a large percentage of the overall decline in investment in equipment, strongly suggests that projects that involved the use of refined copper were at the heart of the initial investment decline that launched the Great Depression.
There is a potential objection that can be made to this version of events based on the breakdown of copper utilization by sector summarized in Table [ ] below.