This problem is the focus of an important new study by Demographia.

FORBES: Why Affordable Housing Matters

To give you an idea of how widespread the problem is, a new study to be published in the Journal of Finance and Quantitative Analysis finds that option volume in a specific stock begins to surge three days before unannounced analyst upgrades or downgrades of a company.

WSJ: Insider Trading's Smart Cheats

The problem with the study, Diet Soft Drink Consumption is Associated with an Increased Risk of Vascular Events in the Northern Manhattan Study ( Gardner et al., Journal of General Internal Medicine) is that the numbers are low enough to leave us uncertain as to whether diet drinks were the cause or simply correlated with other factors that led to these events.

FORBES: Will Drinking Diet Soda Increase Your Risk For A Heart Attack?

And even if we were able to settle upon an acceptable definition of consciousness, we really have no idea how to study the problem.

ECONOMIST: Cut out the middle men