More than 7 million U.S. adults are in the shallow end of the start-up pool, trying to develop the skills needed to deal with the deep water. Each is learning the right skills in a different way; all who are successful master the basics. Most of those who become successful find out rather quickly, in less than a year. Others may spend a lot of time several years fooling around in the shallow end before they climb out of the pool. But the starting of business in a dynamic process, with a constant shifting as new people jump in, others successfully negotiate the deep end, and others climb out of the shallow end. It is also clear that some who leave the pool, whether they're successful or unsuccessful, go back in for another try.