The Cotton Fiber and Processing Test Results Survey for 1986 reported HVI strength values for Deltapine Acala 90 cottons that were significantly higher than similar reference laboratory measurements (Stelometer and Pressley). Since the reference methods compares more favorably with expected yarn strength values, we investigated several HVI design factors that may cause strength level differences. Included were: bundle mass measuring errors (micronaire and humidity), equilibrium moisture content, the effect of aging on specimen preparation, and extension rates. The latter appear to dominate. Results of these investigations are discussed.