They suggest that the business case for HS2 is based on an overly-optimistic prediction of growth in demand for long-distance train travel.

BBC: HS2 compensation to be 'comprehensive'

That is a relatively optimistic prediction, for it would merely return the bankruptcy rate close to its long-term average after an abnormally trouble-free period, and it assumes only a mild recession in America.

ECONOMIST: Bankruptcies in America

Yes, the 2012 London Olympics budget had to be adjusted to account for over-optimistic prediction, but if the human spirit were not optimistic, would there be anyone around to participate in the actual Games?

CNN: Why we fool ourselves into optimism

He thinks the Department of Health's prediction is optimistic and the number of people to give up is likely to be between 80, 000 and 200, 000.

BBC: NEWS | UK | Magazine | Countdown to lights out

Its 2008 estimate is in line with the government's (between zero and 0.5%), but more optimistic than the IMF's April prediction of 0.3%.

ECONOMIST: Italy��s government

While my prediction of 8.5 percent growth proved a bit too optimistic, I was more right than those who predicted a hard landing.

FORBES: Wrapping Up The Year Of The Dragon

At the very least, then, Fat Land's original prediction that obesity "might" break our health care system seems optimistic.

NPR: Rabid Reader: 'Fat Land' and U.S. Supersizing

This mixed opinion makes it difficult to make any prediction for the future, but what is clear is that companies with a positive or optimistic view of the US economy will be more likely to want to drive innovation and change.

FORBES: Innovation and Growth: Which Comes First, the Chicken or the Egg?