The chain-linked model or Kline model of innovation was introduced by Stephen J. Kline in 1985, and further described by Kline and Rosenberg in 1986. The chain-linked model is an attempt to describe complexities in the innovation process.
In the chain-linked model, new knowledge is not necessarily the driver for innovation. Instead, the process begins with the identification of an unfilled market need. This drives research and design, then redesign and production, and finally marketing, with complex feedback loops between all the stages. There are also important feedback loops with the organization's and the world's stored base of knowledge, with new basic research conducted or commissioned as necessary, to fill in gaps.
It is often contrasted with the so-called linear model of innovation, in which basic research leads to applied development, then engineering, then manufacturing, and finally marketing and distribution.
The Kline model was conceived primarily with commercial industrial settings in mind, but has found broad applicability in other settings, for example in military technology development. Variations and extensions[vague] of the model have been described by a number[who?] of investigators.