The report -- funded by the National Association of Home Builders -- says that laws requiring companies to sell some below-market-price housing among more expensive ones "do not come without cost":

We find that inclusionary zoning policies had measurable effects on housing markets in jurisdictions that adopt them: the share of multifamily housing increases; the price of single family houses increases; and the size of single family houses decreases.

This, the researchers say, comes despite the fact that most of the inclusionary zoning laws "offer some form of incentives or compensation for providing affordable units" such as "density bonuses, waivers of subdivision requirements, or fee reductions."

The National Center for Smart Growth Research and Education at the University of Maryland prepared the study. Click HERE to go to the site that has the study (right now, it's at the top of the "In the News" list) and HERE for a press-release summation.

Thoughts? Opinions? Arguments? 

Remember, the study was California only. But in case you're wondering, the University of Maryland researchers note that Montgomery County's Moderately Priced Dwelling Unit program mandates that between 12.5 and 15 percent of the homes in every development of at least 20 units be "moderately priced." In exchange, the builders get to construct more homes overall than the zoning would normally allow -- up to 22 percent more.

Montgomery's law has been in place for a generation. The city's is much newer. Details from the University of Maryland:

In June 2007, the city of Baltimore also enacted an inclusionary zoning statute that calls for 10 to 20 percent of new homes in developments of 30 units or more to be affordable to people with a range of incomes. Requirements vary depending on whether a development benefits from a city subsidy or a rezoning and in some instances will not go into effect until December 2008.

Interested in Howard's law? Read a bit more about the program HERE.