If you are interested in characterizing the material and comparing different material types, the 0.2% offset method is probably the best method because it is used in industry and is repeatable. It is also preferable to use standardized tensile specimen geometries to avoid geometric variation. However, if you are going to use this yield stress in a material model or plasticity code, such as an FEM, you may want to backcast the yield stress based on the plastic deformation properties of the material. This will reduce the error in simulations or subsequent calculations. It is important to note that the “yield point” as we usually use it does not exist: This is a convenient way to quickly characterize and describe material properties. Depending on what you want to know about your material (or its application), another definition of yield strength may be more appropriate.