As resources dwindled, manpower-intensive caucus states were abandoned in favor of delegate-rich primary battlegrounds, a critical error that allowed Obama to amass a pledged delegate lead that Clinton was never able to overcome.

CNN: Analysis: Why Clinton's bid failed

That poll questioned 400 likely Democratic primary voters and has a sampling error of plus or minus 5 percentage points.

CNN: 150 delegates up for grabs Tuesday

So did her reluctance to admit error, as many primary voters urged her to do over her Iraq war vote.

CNN: Analysis: Why Clinton's bid failed

The poll was conducted after Tuesday's primary results and carries a margin of error of plus or minus 4 percentage points.

CNN: Obama, Clinton tied in race for superdelegates

The poll questioned 600 likely Democratic primary voters and has a margin of error of plus or minus 4 percentage points.

CNN: 150 delegates up for grabs Tuesday

Barker and Phillips studied data obtained from the death certificates of people who died in hospital settings between 1979 and 2006, culling those for which medication error was listed as the primary cause of death.

FORBES: What Is the "July Effect" - And Can It Really Kill You?

America's primary export, it appears, is trial-and-error, and the innovative knowledge attained in such a way.

FORBES