Cotton fiber length is measured using a variety of instruments and methods yielding a wide range of length parameters (mean lengths, length percentiles, short fiber content, length uniformity index, length coefficient of variation…). Among all the parameters made available by the existing range of instruments, the Uniformity Index (or the uniformity ratio) represents the only commonly used shape parameter of the length distribution. This paper presents a progress report on an alternative approach to characterizing the shape of the entire distribution of cotton fiber length. It explores the distribution's main features and identifies the interaction effects that determine it shape.