The need to ensure the repeatability and reliability of mechanical test results between individual test systems, whether those systems are located in the same lab or different labs or a comparison is being made between multiple suppliers, has recently surfaced as a critical concern throughout the medical device industry.  This is not surprising since product quality is critical and quality assurance depends on the ability of testing systems to provide accurate results.  Further, as many industries expand R&D and manufacturing operations into different parts of the world, data comparisons have become increasingly more important and complex.  Gage repeatability and reproducibility, also knows as GR&R, is a type of statistical analysis that is often performed by quality and product engineers as a method of test equipment validation and verification.  However, in cases where GR&R values are higher than expected, it is necessary to investigate and resolve or at least minimize sources of variation.  The purpose of this paper is to highlight a variety of error sources and provide suggestions and guidelines for conducting a successful GR&R study.