Abstract: Improved method, and apparatus for practicing the method, for determining parameters of a staple length distribution of fibers in a yarn sliver by feeding the yarn sliver to and between two pairs of drafting rolls initially spaced apart at a greater distance than the longest fiber in the yarn sliver and monitoring the drafting force exerted upon the yarn sliver while continuously decreasing the distance between the pairs of drafting rolls and monitoring the distance, and generating signals representative of the drafting force and distance and feeding them, respectively, to the Y-axis and X-axis of a X-Y recorder and drawing a curve therefrom from which the desired parameters can be determined.