The Radiocarbon Dating Laboratory has participated in three international crosscheck programs. These quality assurance programs are essential to insure data integrity (excellence) and user confidence by providing an objective crosscheck and verification of different facilities worldwide. The first program, International Collaborative Study, took place between 1986-88; the second study was a quality assurance program organized by the International Atomic Energy Agency (Vienna) in 1990; and the Third International Radiocarbon Intercomparison (TIRI) was coordinated by Glasgow University between 1993-94 and involved 75 laboratories worldwide. The GSC has consistently performed in the top 10% on these international intercalibration studies. These international quality assurance / quality control programs benefit all GSC clientele and are essential for the establishment of the chronologic, stratigraphic, and environmental history of Quaternary deposits in Canada.