The rich get richer and the poor get poorer

"The rich get richer and the poor get poorer" is a catchphrase and aphorism sometimes evoked, with variations in wording, when discussing economic inequality. Its most common use is as a synopsis of a socialist criticism of the free market system (capitalism), implying the perceived inevitability of what Karl Marx called the Law of Increasing Poverty.

Predecessors

Andrew Jackson, the seventh President of the U.S. (1829–1837), in his 1832 bank veto, said that

William Henry Harrison, the ninth President of the U.S. (1841), said in an October 1, 1840 speech,

In 1821, Percy Bysshe Shelley argued, in A Defence of Poetry (not published until 1840), that in his England, "the promoters of utility" had managed

The phrase resembles the Bible verse

"Ain't We Got Fun"

The phrase was popularized in 1921 in the wildly successful song "Ain't We Got Fun?", and the phrase is sometimes attributed to the song's lyricists, Gus Kahn and Raymond B. Egan. The line is sometimes mistakenly attributed to F. Scott Fitzgerald. It appears in The Great Gatsby, as

The rich get richer (statistics)

In probability and statistics, the phrase "the rich get richer" is used to describe the self-reinforcing behavior of certain probability distributions and stochastic processes, such as the Dirichlet process and Chinese restaurant process. Note that this behavior is seen in the context of many, perhaps most, distributions, when considering a sequence of independent identically distributed observations drawn from a probability distribution with unknown parameter and examining the conditional distribution of one observation given all previous ones. For example, if an observation is drawn from a Gaussian distribution with unknown mean (with uncertainty expressed by a prior distribution over the mean), then the posterior distribution over the mean will be shifted towards the observation, and the next observation will have a higher probability of being similar to the previous observation than it was under the prior distribution. In this case, regions that are "rich" in the sense of containing a large fraction of the observations are quite likely to get richer, whereas poor regions are less likely to get richer.