The Working Group on the Rotation of the Earth was established in 1978. It developed MERIT, a program of international collaboration to monitor earth rotation and intercompare the techniques of observation and analysis. The MERIT Short Campaign was held in 1980 to test and develop the organizational arrangements that were required during the MERIT Main Campaign (1983–1984). The Working Group on the Terrestrial Reference System was created in 1980 to prepare a proposal for the establishment and maintenance of a new Conventional Terrestrial Reference System (COTES) that would be based on the new techniques of space geodesy. The two working groups collaborated closely on two intensive campaigns in 1984 and 1985 that were aimed primarily at determining the relationships between the reference systems of the six different techniques that were used to determine earth rotation parameters. Observational data were obtained from 35 countries, and analyses and intercomparisons of results were carried out in seven countries. The working groups reviewed the results at the Third MERIT Workshop. They recommended that a new International Earth Rotation Service be set up in 1988 and that it should have as its basis the use of very long baseline radio interferometry and both satellite and lunar laser ranging. The complete report of the working group has been published in the Bulletin Geodesique, vol. 60, pp. 85–100, 1986.