「金持ちはより金持ちに、貧乏人はより貧乏に」(かねもちはよりかねもちに、びんぼうにんはよりびんぼうに、英語: The rich get richer and the poor get poorer)は、パーシー・ビッシュ・シェリーによる英語の格言である。詩集『詩の擁護(英語版)』(1821年執筆、1840年刊行)の中で、シェリーは次のように書いている。
[The promoters of utility had] exemplified the saying, "To him that hath, more shall be given; and from him that hath not, the little that he hath shall be taken away." The rich have become richer, and the poor have become poorer; and the vessel of the State is driven between the Scylla and Charybdis of anarchy and despotism.[1]
when the laws undertake... to make the rich richer and the potent more powerful, the humble members of society... have a right to complain of the injustice to their Government.[3][4]
統計学では、"the rich get richer"というフレーズは、中華料理店過程などの優先アタッチメント(英語版)過程の振る舞いの略式の説明としてよく使用される。すなわち、特定の値をとる一連の結果の次の結果の確率は、その特定の値をすでに持っている結果の数に比例する。これは、人気投票などの現実世界の過程をモデル化するのに役立つ。すなわち、特定の選択肢に人気があると、新しい参加者がその選択肢を採用するようになる(最初の数人の参加者の影響が大きくなる可能性がある)。
^“HC S: [Confidence in Her Majesty's Government”]. House of Commons Speech (Hansard HC [181/445-53]) (22 November 1990). (1990年11月22日). http://www.margaretthatcher.org/document/1082562016年5月2日閲覧. "People on all levels of income are better off than they were in 1979. The hon. Gentleman is saying that he would rather that the poor were poorer, provided that the rich were less rich. That way one will never create the wealth for better social services, as we have. What a policy. Yes, he would rather have the poor poorer, provided that the rich were less rich. That is the Liberal policy."
Hayes, Brian (2002). “Follow the Money”. American Scientist90 (5): 400. doi:10.1511/2002.5.400. — Hayes analyzes several computer models of market economies, applying statistical mechanics to questions in economic theory in the same way that it is applied in computational fluid dynamics, concluding that "If some mechanism like that of the yard-sale model is truly at work, then markets might very well be free and fair, and the playing field perfectly level, and yet the outcome would almost surely be that the rich get richer and the poor get poorer."
Rieman, J. (1979). The Rich Get Rich and The Poor Get Poorer. New York: Wiley
David Hapgood (1974). The Screwing of the Average Man — How The Rich Get Richer and You Get Poorer. Bantom Books. ISBN0-553-12913-9
Rolf R Mantel (1995). Why the rich get richer and the poor get poorer. Universidad de San Andrés: Victoria, prov. de Buenos Aires. OCLC 44260846
Ispolatov, S.; Krapivsky, P.L.; Redner, S. (1998). “Wealth distributions in asset exchange models”. The European Physical Journal B2 (2): 267–76. arXiv:1006.4595. Bibcode: 1998EPJB....2..267I. doi:10.1007/s100510050249. — Ispolatov, Krapivsky, and Redner analyze the wealth distributions that occur under a variety of exchange rules in a system of economically interacting people.
Chung, Kee H.; Cox, Raymond A. K. (1990). “Patterns of Productivity in the Finance Literature: A Study of the Bibliometric Distributions”. The Journal of Finance45 (1): 301–9. doi:10.2307/2328824. JSTOR2328824. — Chung and Cox analyze a bibliometric regularity in finance literature, relating Lotka's law of scientific prductivity to the maxim that "the rich get richer and the poor get poorer", and equating it to the maxim that "success breeds success".