Realtor.com asks an intriguing question involving McMansions – “So which are America’s housing markets with the biggest cribs, and why?” – but then does not follow through because of a limited definition of which homes count as McMansions:

We sifted through realtor.com listings to figure out which of the 150 largest metros had the highest percentage of homes on the market that are 3,000 square feet and above. (The average square footage of a new single family home is 2,627, according to the National Association of Home Builders’ analysis of U.S. Census Bureau data.) Sure, this includes some tasteful, large homes and legit mansions. But it was impossible to separate those from the McMansions—it’s rare to see the word “tacky” in a home listing.

There are plenty of big homes in the United States – the median square footage of a new home is over 2,400 square feet – but not all big homes are McMansions. The article provides a different definition for McMansions than the one they actually use with the data:

The imposing, ostentatious structures looming over surprisingly wee plots of land. The crazily mismatched architectural styles. The hipped roofs, gabled roofs, and pyramidal roofs—all on the same house! The bank columns. The front yard Romanesque fountains. The puzzling profusion of window sizes and types. The gigantic, two-story front doors.

I can understand how the real estate listings do not easily allow for the easy categorization of homes as McMansions. Few, if any, homeowners and realtors want to advertise their homes using such a pejorative term. Yet, if you are going to use a headline involving McMansions and then talk about the poor architecture of McMansions, then your measure should take these features into account.

How might this be done? A few ideas:

1. Take random samples within each metropolitan area and look for specific features.
2. Do a survey of realtors, architects, and others who might be able to identify McMansions to get their sense of how many McMansions are in particular areas.
3. Train a computer program to scan thousands of images of homes for sale and determine whether the homes are McMansions or not. (The coding scheme would be very similar to the one used in #1.)

These approaches are not necessarily easy but would be essential for actually getting at which AMerican cities have teh most McMansions.

For a more complete definition of a McMansion – including but also beyond their size and architecture, see my summary here.