Inequality has been seizing ever more of the public’s attention in recent years, reflected everywhere from papal encyclicals and economic tomes by French socialists to technical academic debates and the demotic language of politicians and pundits. The health and economic effects of the Covid-19 pandemic have further elevated these concerns.

But which aspect of inequality should we be worried about? There are inequalities of opportunity and inequalities of outcome; there is overall inequality and there is inequality at the tails of the distribution. Should we be more worried about absolute or relative positions – mobility or stability? What is really more important, the distribution of the economic pie or the level and growth of living standards?

In China over the past four decades, inequality has soared, even as hundreds of millions of people have been lifted out of abject poverty. In the US today, after-tax per capita GDP is 50% higher than in less unequal Denmark and Sweden, where higher taxes fund huge welfare systems. Among the US states, California has the highest poverty rate once one adjusts for its 20% higher average household size and 15% higher cost of living.

Moreover, consumption and disposable income are considerably less unequal than the oft-quoted market income figures. Average measures taken over a longer term tend to show less inequality, reflecting the fact that many people are poor or rich only temporarily. Many of my university students currently have low incomes but will almost certainly be very well off later in their lives. It is not surprising that natural age-earnings profiles and measures of life-cycle wealth accumulation would show considerable inequality at any point in time. All data sources have strengths and limitations, be it sample size, frequency, item coverage, or comparability (especially relevant in the case of international data).

Accounting as best as I can for these factors, I have compiled the following summary of major trends in US inequality in recent decades. Since around 1980, the skill premium in wages has grown substantially, whereas lower-skill real (inflation-adjusted) wages have grown more slowly (not to be confused with a decline). This reflects technology’s bias towards skilled labour, globalisation’s negative effects on less-skilled wage earners and the composition of labour-skill supply and demand.

During this period, overall inequality increased in almost all advanced economies (though some believe it will reverse), suggesting that domestic policies could not have been the primary cause. Similarly, after a long period of stability, labour’s share of national income has declined in all major economies.

Meanwhile, though social mobility has remained at considerable levels, it likely declined, including intergenerationally. Changes in the wage distribution have been concentrated mostly in the top half, and though there has been a relative increase in wealth at the very top, it is less than some commentators claim.

Indeed, there has been a huge increase in cash and in-kind transfer payments. One-sixth of US income comes from such payments, and the rate in western Europe’s social-welfare states is even higher. The US’s unfunded entitlements liabilities have grown to several times the already high national debt.

While inequality in disposable income (and even more so in consumption) remains substantial, it is much lower than inequality in market incomes. After adding transfers and subtracting taxes, one finds that the income of the top 1% in the US falls by more than one-third, while that of the bottom 20% triples.

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