[gnicholas]

It's possible the decrease is driven largely by spending habits of low-income families:

> Last year, researchers at the University of Washington found that low-income families in particular saw a significant decrease in soda consumption following the implementation of the tax. The findings were based on a survey of residents, meaning that it relied on self-reporting, which is less accurate than sales data.

This leads to interesting policy questions. For example, some people might complain that the tax is regressive and hits poorer families harder. A rebuttal to this is that obesity is also regressive, and if you wish to fight obesity you need to change behaviors of the people whom it afflicts. One way around this knotty issue is to take the money from this tax and use it for public services that disproportionally benefit the populations from whom it is generated. (I have no idea what the tax revenues in Seattle are used for.)

[bertjk]

> One way around this knotty issue is to take the money from this tax and use it for public services that disproportionally benefit the populations from whom it is generated. (I have no idea what the tax revenues in Seattle are used for.)

And now you've created a bureaucracy that can only maintain its existence if sugary drinks continue to sell well.

[inglor_cz]

Or if the sin tax is gradually expanded to cover almost everything in the grocery store.

[idontwantthis]

> It's possible the decrease is driven largely by spending habits of low-income families:

Which I think, isn't really caused by their low-income, but by their greater preference for soda.

Demand changes at the margin, so a $.20 increase is a $.20 increase to everyone. It depends how much you value the soda in the first place.

[gnicholas]

The price elasticity of demand (i.e., the amount someone changes purchasing decisions based on price changes) depend in part on how much of your budget the item takes up. For wealthy people, soda is a rounding error on a rounding error. For lower income folks, soda could be a small but noticeable percentage of their budget. So 20¢ is not 20¢ to everyone.

For my part, I know that teenager-me would have absolutely noticed this price increase, but adult me would not.