Kondratieff wave

In the theory of economics, Kondratieff waves, also referred to as the K-waves, are the description of an alleged regular S-shaped cycle in the modern world economy. Fifty to sixty years in length, it consists of an alternation of periods of high sectoral growth with periods of slower growth. The pattern is more visible in international production data than in individual national economies and concerns output rather than prices.

They were developed by Russian economist Nikolai Kondratieff in the 1920s. His ideas were endorsed by Joseph Schumpeter in the 1930s, who named the pattern after Kondratieff.

According to Kondratieff's theory, K-waves arise from the bunching of basic innovations that launch technological revolutions that in turn create leading industrial or commercial sectors.

de:Kondratjew-Zyklus