Ainda a progressividade fiscal

A discussão sobre a progressividade do IRS tem-se centrado muito num ponto: a proporção das receitas do IRS que vêm dos impostos pagos pela classe alta.

Ora isso (grande parte do IRS ser pago ou não pela classe alta) é, por si, irrelevante para avaliar da progressividade ou não do imposto.

Feito a pensar no contexto bitânico (onde está a haver uma discussão muito semelhante), este exemplo extremo revela bem isso:

Imagine a society of 100 people run by a rapacious dictator and his henchmen. This dictator has an income of 1000 and his four henchmen an income of 500. The other 95 people have an income of 10. And imagine too that the dictator has rigged the tax system so that he and his cronies pay 10% of their income in tax whilst the other 95 pay 20%.

Is this society just or equal?Most of us would say not. Most of us, that is, except Fraser Nelson.

He says:

The richest 1% of this country pay 23% of all income tax collected in 2008-09. The richest 5% pay 42% of the tax. These ratios should warm the heart of the most ardent redistributionist.

They shouldn’t. Think of the equivalent figures in my example. The richest 1% of earners - the dictator - pays 20.4% of all tax.

The top 5% pays 61.2% of all tax. But these ratios, and this society, would not “warm the heart” of any redistributionist.

My example shows that if inequality is high enough, even a regressive tax system will involve the rich paying a large share of tax.

What’s more, if inequality rises, so too will these ratios. If our dictator and his cronies rob the poor of half their income and divide it among themselves, the share of total taxes paid by the top 1% will rise from 20.4% to 24.7%, whilst the share paid by the top 5% will rise to 78.5%. By Fraser’s reckoning, our society has become more redistributionist. Which it has - but in precisely the opposite direction that Fraser would think.

So, the share of taxes paid by the rich tells us nothing about whether society is equal or the tax system progressive. To believe they do is to commit a plain logical error.