The Pareto principle is the principle, discovered by the Italian economist Vilfredo Pareto, that '20 percent of inputs lead to 80 percent of outputs'; in the incelosphere, and the manosphere in general, it refers to the observation that dating prospects are not always distributed evenly. While there is not necessarily evidence that human sexual endeavors follow a strict Pareto distribution, it is used a 'rule of thumb' in the incelosphere that illustrates the concept of female hypergamy. This does not mean that advocates of applying this principle to dating are implying that only 20 percent of men have sex. It is only claimed that sexual access (and therefore copulation frequency) is unevenly distributed among the male population. See the 80/20 Rule for more.