For the last two years, multifamily construction starts and permits have been slowing. Now the downturn has extended to single-family housing, writes RealPage Senior Real Estate Economist Chuck Ehmann. What that might mean is complicated.

RealPage looked at seasonally adjusted annual rates (SAAR), which means it's time to check for a caveat. Remember that seasonally adjusted rates mean someone is shifting actual data to account for how they think periodic forces and patterns might affect results. It's a normal strategy in economic analysis and can be useful, but risks missing changes in markets and events.

A GlobeSt.com review of seasonally-adjusted and non-seasonally-adjusted government multifamily housing start data shows the two to be very close. The same is true for multifamily permits, again using government data. For single-family permits and starts, non-seasonally-adjusted figures show more volatility than seasonally-adjusted, but the overall shifts seem similar. The approach seems reasonable.