The idea that movements in a time series tend to be part of larger trends and cycles more often than they are completely random. The Joseph Effect is quantified by the Hurst component, where movements fall between a Hurst range of 0 to 1. The term was coined by Benoit Mandelbrot.
If a series of movements is calculated to be between 0 and 0.5 in the Hurst range, then the movement is larger and more random than what are thought to be normal random movements. If the measure is 0.5, then the movements are thought to be random movements. If it is between 0.5 and 1, the movements are thought to be part of a long-term trend. The term "Joseph Effect" alludes to an Old Testament story about Joseph, where Egypt would experience seven years of feast followed by seven years of famine.