Four different HVI Strength Indices were developed for predicting the yarn tensile properties. The "HVI Strength Indices were formed based on HVI tenacity, modulus, toughness and micronaire. The concept of "Best Power Function Search" was developed and applied to formation of two HVI Strength Indices (Q₃ and Q₄). The new indices (Q₃ and Q₄) derived from the best power function regression search were found to be superior to that without (Q₁ and Q₂).