There has been some confusion between the terms long-cycle and long-waves. Long-waves date back to Nikolai Kondratieff, the Russian economist whose name now represents the cycles that he expounded on, that is the Kondratieff Waves. Long-cycles properly belongs to Simon Kuznets, the second American to win the Nobel Prize in economics, (the first being Paul Samuelson). Long-cycles, also known as long-swings, originally referred to the cycles that Kuznets expounded on, now known as Kuznets cycles or simply Kuznets. With much confusion about these terms over the last 30 years, long-cycles is used almost interchangeably to refer to long-waves by economists, sociologists and writers alike and few really know the difference.
While Kondratieff's long-waves were thought to be about 50 to 60 years long, Kuznets' cycles are much shorter, based on his work with mid 19th and early 20th century demographics. Edward Cheung, author of Baby Boomers, Generation X and Social Cycles, suggests that both these cycles are based on demographics and that they do not contradict each other, but complement each other.