how do we now write standard method here, which goes back to economists glaeser and gyourko is to take a look at very similar that have different amounts of land and then use the extra price of the house, the extra land measure. what is the value land that does not have the actual permission to build anything on go for what is that price right and. what they find is that the extra will pay to have 100 square feet of vacant unusable land for anything other than walking around or playing volleyball is real. well then you got this pure value of land. next step is go to a big manual of construction cost used by people who actually industry and figure out what is the physical construction cost to actually make the home right. then finally you sum the cost of the unimproved land with the cost of construction to price and that gap is the measure the effect of regulation which is often somewhat confusingly called the zoning tax. sometimes perhaps some are knows about zoning says well, it isn't really a tax. yes, the researchers know this. they just want to have a name for what regulation is ad