You've probably seen the headlines or heard the chatter: Multifamily construction is at the highest levels in 50 years. There are about 1 million multifamily units actively under construction nationally. But to say multifamily construction is at a 50-year high is equally true and terribly misleading. Why? Three reasons.

There are roughly 2.5 times more multifamily units in the U.S. today than there were in 1970. 

So that means 1 million units today has nearly one-third the impact that it had back in the early 1970s. In other words: The total number of units under construction doesn't tell the full story. It's the relative expansion rate that matters more. At peak, new supply expanded the U.S. multifamily stock by 6.5% in 1973. At peak in this cycle, the inventory expansion rate will measure 2.2%, according to analysis of U.S. Census Bureau data.