> 1. This report only looks at the 100 most populous metropolitan areas. A list that wouldn't include Reno NV or Montgomery AL. I understand that these 100 areas represent over half the population, but they also represent more expensive homes than the places not studied. This skews the percentage, and the title is over generalizing.

In addition to this excellent point, you'd also expect a larger number of homes to be unaffordable to the typical household given some realistic assumptions (eg, housing is a major expense in the modern West) - and it doesn't appear they are correcting income for regions in the same way they are only selecting real estate.

So they are taking the more expensive regions comparing to the country-wide income and not pointing out that we;d expect maybe up to 50% of homes to be unaffordable anyway.