Inequality is a major international development challenge. This is so from an ethical perspective and because greater inequality is perceived to be detrimental to key socioeconomic and political outcomes. Still, informed debate requires clear evidence. This article contributes by taking stock and providing an up-to-date overview of the current knowledge on the impact of income inequality, specifically on three important outcomes: (1) economic growth; (2) human development, with a focus on health and education as two of its dimensions; and (3) governance, with emphasis on democracy. With particular attention to work in economics, which is especially developed on these topics, this article reveals that the existing evidence is somewhat mixed and argues for further in-depth empirical work across disciplines. It also points to explanations for the lack of consensus embedded in data quality and availability, measurement issues, and shortcomings of the different methods employed. Finally, we suggest promising future research avenues relying on experimental work for microlevel analysis and reiterate the need for more region- and country-specific studies and improvements in the availability and reliability of data.

中文翻译：

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关于不平等对增长、人类发展和治理的影响

不平等是一项重大的国际发展挑战。从伦理的角度来看是这样，因为更大的不平等被认为对关键的社会经济和政治结果有害。尽管如此，知情辩论仍需要明确的证据。本文通过评估和提供有关收入不平等影响的当前知识的最新概述做出贡献，特别是在三个重要结果方面：（1）经济增长；(2) 人类发展，重点关注健康和教育两个维度；(3) 治理，强调民主。本文特别关注在这些主题上特别发展的经济学工作，本文揭示了现有证据有些混杂，并主张跨学科进一步深入的实证工作。它还指出了对数据质量和可用性、测量问题以及所采用的不同方法的缺点缺乏共识的解释。最后，我们建议未来有希望的研究途径，依赖于微观分析的实验工作，并重申需要进行更多区域和国家特定的研究，并提高数据的可用性和可靠性。