In economics, Kondratiev waves are hypothesized cycle-like phenomena in the modern world economy. The phenomenon is closely connected with the technology life cycle.
Kondratiev waves associated with gains in IT and health with phase shift and overlap, Andreas J. W. Goldschmidt, 2004
Image: Long Waves Three Paradigms
Business cycles are intervals of general expansion followed by recession in economic performance. The changes in economic activity that characterize business cycles have important implications for the welfare of the general population, government institutions, and private sector firms. There are numerous specific definitions of what constitutes a business cycle. The simplest and most naïve characterization comes from regarding recessions as 2 consecutive quarters of negative GDP growth. More satisfactory classifications are provided by, first including more economic indicators and second by looking for more informative data patterns than the ad hoc 2 quarter definition.
Phases of the business cycle
Business cycle with it specific forces in four stages according to Malcolm C. Rorty, 1922
Economic activity in the United States, 1954–2005
Deviations from the long-term United States growth trend, 1954–2005
