In many other countries, small businesses are a principal engine of economic growth.
So far, it has not hurt consumption, the principal engine of the American economy.
People are accustomed to the idea that investment is the principal engine of China's extraordinary expansion.
Russia and Brazil have both fallen into recession, while China, the principal engine of world growth, has seen a sharp contraction in overall economic activity.
Energy consumption is falling in both industrialized nations like the United States and developing countries like China, which had been the principal engine of new growth over the past decade.
But they most likely will not see the light of day for three more months, until a rescue shaft can reach them, and so they stand as a constant reminder, just off center stage, of how dependent Chile remains on exports of natural resources as the principal engine of its economy.
In discussing what she portrays as a decline in the American job market, for example, Klein avoids the debate over increased productivity, as well as the fact that small businesses, rather than brand-crazed multinationals, have been the principal engine of job growth for many years.
Describing the changes in AOL's business, Mr. Case said he believed that online advertising, once the principal engine of AOL's profits and growth, would become less important than other sources of revenue, like subscriptions, fees for premium services and sales of goods and services to members online.
The principal engine for the evaluation of treatment efficacy is the randomized controlled trial (RCT).
