In the late 1960s, Klein felt it necessary to establish an overall international economic model. With the support of the International Fund and the National Science Foundation of the United States, from 65438 to 0968, Klein initiated an action at a meeting of Stanford University, which brought together modelers from major countries of the Organization for Economic Cooperation and Development, and established a set of continuous international equations to analyze the mutual influence and connection between national economies. This is a linked project. In fact, the link plan is an international contact model of national economies. Klein is in charge of this project together with Porter hickmann of Stanford University, Rudolf Lomborg of the International Monetary Fund and aaron gordon of the University of California.

Klein spent a lot of time and energy on the Link project, which now includes underdeveloped countries, planned economy countries and OECD countries. In Klein's view, Link system is faster, cheaper and easier than any system used before. In addition, participating researchers all over the world can now use audio-visual telecommunications systems to obtain enough information on computer screens supporting the network.