The short answer … magnets:
The long answer? You’ll have to go read the post. However, I will give you this here:
In today’s article we discussed progressivity, and the complicated interrelationships between ideas of equity and efficiency.
Given these difficulties, it is important for policy makers and researchers to clearly communicate the trade-off that exist – so that an informed public can come to some conclusion about what they think is fair.
While the principles of tax we recently mentioned helped us to understand some of the interrelationships, the importance of elasticity in determining who actually pays a tax was made apparent here – just saying “I want that person to pay” doesn’t work when they can pass the buck on or shift away from paying tax altogether.
Furthermore, even if higher tax rates are able to redistribute income (in terms of the goods and services available to different income groups) the impact on people’s willingness to supply labour and the wedge between the private and social benefits of someone’s decision to work does imply there are efficiency costs from doing so.
In many ways it is an extension of this article – given that the reader is now assumed to have some idea about horizontal and vertical equity, poll taxes, factor taxes, and output taxes (which were the intervening articles).