Previous studies on the optimization of injection molding from various standpoints have shown that transferability alone provides only an extremely small gain and repeatability cannot be determined with adequate reliability, The reason was considered to lie in the processing of nonlinear effects. This time we reanalyzed transferability and shape retention by the standard signal-to-noise ratio, using a crystalline resin test piece. As a result, it became clear that uniform fillability is essential for transferability, and if this condition is not satisfied,shape retention is unsatisfactory.