This publication introduces a new mathematical model to describe a definitive relationship between constant strain-rate, creep, and stress-relaxation analysis for viscoelastic polymeric compounds. This new concept is especially significant since it adequately describes all the important characteristics of both creep and stress relaxation in the same model. In particular, all three phases of creep (i.e., primary, secondary, and tertiary) can be described adequately using this model. This new model for polymeric materials also indicates that yielding for constant strain-rate measurements and the inception of tertiary creep appear to be directly related and may, in fact, be manifestations of the same phenomena. The initial buildup of stress followed by the drop off in stress as a function of time for stress relaxation is also adequately described. This new formulation approach also offers a reasonably simple process in which to shift from a constant strain-rate configuration to a creep calculation or stress-relaxation configuration without changing formulation considerations. Most importantly, this model can be used to make a transition from one of these stress-configuration modes to another without stress or strain discontinuities. It is hoped that this analysis approach will open new doors for the design of plastic products for both short-term and long-term applications.