Many testing techniques and interpretative methods are currently used to determine the strength parameters of saturated clays. The physical circumstances under which clays are likely to be well-behaved are described in this paper. A well-documented procedure for determining the effective stress-strength parameters of such materials is recommended. The direct shear and triaxial compression tests are examined. Other tests or modifications can be conducted, but these are not in common use (eg, triaxial extension). The point is made that soils often exhibit different properties, depending on the type of testing (eg, plane strain or radial symmetry).(Author)