 Pilling is a function of fiber content, spinning method, twist, contiguous staple length, and fabric construction.Single ply yarns or using fibers like merino wool are known to pill more due to the fact that in the former, the single ply is not tight enough to securely retain all the fibers under abrasion, and the merino wool's short staple length allows the ends of the fibers to pop out of the twist more easily.Yarns combining synthetic and natural fibers inherit the properties of each parent, according to the proportional composition.