There he built a model of the United States economy to forecast the development of business fluctuations and to study the effects of government economic-political policy.

After World War II Klein used his model to correctly predict, against the prevailing expectation, that there would be an economic upturn rather than a depression due to increasing consumer demand from returning servicemen.

[5] In 1954, Klein's brief membership in the Communist Party was made public[1] and he was denied tenure at the University of Michigan, in the wake of the McCarthy era.

In the early 1960s Klein became the leader of the major "Brookings-SSRC Project" to construct a detailed econometric model to forecast the short-term development of the U.S. economy.

He was the initiator of, and an active research leader in their LINK project, a consortium of model builders from many countries, which was also mentioned in his Nobel citation.

[citation needed] During the 1976 United States presidential election, Klein coordinated Jimmy Carter's economic task force.

His Nobel citation concludes that "few, if any, research workers in the empirical field of economic science, have had so many successors and such a large impact as Lawrence Klein".

A publication on high frequency model containing regions such as US, China, Russia, India, Brazil, Mexico, Korea and Hong Kong was expected in 2008.