This method provides a measure of the effective length of the fibers in a random, standard aggregate of pulp fibers based on wet zero-span tensile testing. The test requires a zero-span tensile apparatus as described in TAPPI T 273, with the capability not only to conduct a wet zero-span tensile test, but also to conduct the same test with an initial jaw separation of 0.4 mm. The short-span (0.4 mm) tensile strength of the random array of wetted fibers when expressed as a ratio of the zero-span tensile strength of the same wet fiber aggregate, is a measure of the effective length of the fibers in the aggregate.