Formalization and inevitability of the Pareto principle
Antti Hippeläinen
TL;DR
This work asks whether the Pareto principle is a structural property of bounded cumulative processes rather than a universal empirical rule. It formalizes a generalized Pareto principle using a non-negative gain density on the unit interval and a decreasing rearrangement to define a unique, domain-order-independent criterion via $\\mathcal{L}^{(*)}(p) = 1 - p$. The authors establish existence results and analyze both constructed densities and common distribution families (power-law, exponential, normal) to map the attainable $p$ values as functions of distributional form and dataset size, highlighting how tails and truncation shape imbalance. They conclude that Pareto-like imbalances are structural features of gain distributions, with exponential and normal cases typically yielding $p$ near the canonical 0.2, while power-laws yield more extreme imbalances; this cautions against using 0.2/0.8 as a universal benchmark and emphasizes the distribution-specific interpretation of inequality and resource allocation.
Abstract
We formalize and study a generalized form of the Pareto principle or "20/80-rule" as a property of bounded cumulative processes. Modeling such processes by non-negative gain densities, we first show that any such process satisfies a generalized Pareto principle of the form "fraction $p$ of inputs yields fraction $1-p$ of outputs". To obtain a non-trivial and unique characterization, we define the generalized Pareto principle via the decreasing rearrangement of the gain density function. Within this framework, we analyze both constructed gain densities that exemplify the framework and its imposed restrictions, as well as distribution families commonly encountered in datasets, including power-law, exponential, and normal distributions. Finally, we predict commonly encountered ranges for the generalized Pareto principle and discuss the implications of elevating a structural property into a prescriptive role.
