One more scientific-seeming (but complex) measure is energy. Professor Charles Hall adapted the notion of energy return on (energy) investment (EROI, or EROEI) from the biological sphere (where he began his studies) to human social-economic systems. This appears to be a promising method for analysing different forms of commercial energy production.
However, the entry linked above goes on to claim a correlation between the stockmarket and energy usage:
... a century's market and energy data shows that whenever the Dow Jones Industrial Average spikes faster than US energy consumption, it crashes: 1929, 1970s, the dot.com bubble, and now with the mortgage collapse.
I'm not so sure, and I've had a look for the evidence. So far, I've come across a study by the US Energy Information Administration of oil futures vs stock and other indices, and over the admittedly fairly short period covered, the correlation with the Dow is not uniformly high, though it has increased since the Credit Crunch:
Granted, energy usage and energy prices are not necessarily tightly bound together, but does the above tend to disprove or prove the assertion that the Dow cannot long outrun energy use?
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