Between Property and Liability

Last October I posted on Eric Posner and Glen Weyl’s proposal to generalize self-assessed property taxes. For many items, such as land and buildings, you’d pay an annual tax that is a standard percentage of your self-set sale-offer price for the item. This would avoid administrative property valuations, discourage people from sitting on stuff they don’t use, and make it much easier to assemble property into large units. Eminent domain would no longer be needed. They have a new book, Radical Markets, coming out in a few weeks, that I will review soon.

Some libertarian types disapprove on the grounds that this weakens property rights. Which it can, relative to a simple absolute property right. But simple property and liability have long been two quite different, and extreme, solutions to legal problems. Neither one is always best. In this post I want to point out that this alternate approach can be used not only to change traditional property to be more like liability, it can also be used to change traditional liability to be more like property. It is an interesting intermediate form between traditional property and liability. One I expect libertarian types to look on more favorably when applied to liability.

Today if someone smashes their car into yours, you can sue them for damages. But even if you convince the court that the event happened and that the party you sued was at fault, the amount of the damages will be set by a court’s judgement. They will mostly look at your demonstrable financial costs, and mostly ignore your value of leisure time, disability, pain, etc. You can’t do much to convince them that you suffer a higher cost from such events than others do.

To apply self-assessment to liability, we’d ask each person to estimate a function that outputs their loss in dollars, and takes as input different scenarios of events that could hurt them. The function would say how much they suffer in each scenario. (The function might interpolate between a set of concrete scenarios which the person rated.) We’d convolve this function with an official distribution over how often such events happen, and a tax rate function, to find each person’s total tax. This is like paying a tax for each property item you hold, but is instead adding up a tax for each possible scenario where you might be hurt.

Then if someone actually hurts you in some event, you could sue for the amount of damages your function declares for that event. Once the court was persuaded that the event happened and that the person you sued was at fault, the court could mostly just believe your estimate of harm, instead of trying to estimate it themselves. In this way the court could cheaply and accurately account for losses of limbs, time, pain, etc. As you’d set the damage levels yourself, this approach makes traditional liability more like property.

Added 15Apr: A reminder: this doesn’t have to produce any net tax revenue. It could just take from those who declare larger than average values of harms done to them, and rebate to those who declare lower than average values.