An overview of the typical in vitro test methods used to characterize
the performance of Nitinol stents is presented.  This necessitates a
consitent definition and understanding of radial force as well as a
consideration of the sensitivity of the various methods to friction,
fixture compliance, material uncertainty and other experimental
factors.  These sensitivities are demonstrated using finite element
analysis and in vitro experimentation.  The results help guide the
development of better experimental methodologies and interpretation of
performance parameters such as radial force.  Finally we conclude with
recommendations for establishing a rigorous, self-consistent approach
to Nitinol component design, testing and validation.