Median vs. Mean Decline in Housing Prices
The National Association of Realtors recently reported that prices of single-family homes fell by 1.8% in 2007 – the first decrease since the inception of record keeping in 1968 and, likely, the first drop since the Great Depression.
1.8% doesn’t seem like much of a decline, given recent commentary about housing prices approaching free-fall. For example, recall that Merrill Lynch recently forecast a 15% drop in housing prices in 2008 and a further 10% drop in 2009. Such a prognosis appears highly extreme in light of the 1.8% drop in 2007 housing prices.
But there is a catch, in effect. The median can be very different from the mean. The National Association of Realtors was referring to a median housing price decline of 1.8%. Merrill Lynch, in its outlook, was referring to the mean – or average – price decline of single-family homes.
As a reminder, the median is the halfway point. If prices of single-family homes declined by 1.8% in 2007, then half the homes declined by less than 1.8% and half the homes declined by more than 1.8%. If all homes that declined by more than 1.8% dropped in price by 20%, for example, it would not affect the median. The median would remain at a negative 1.8%. In fact, the National Association of Realtors also estimated that the mean, or average, annual decline in single-family home prices in 2007 was 5.3%.
It can all be very confusing. Keep in mind, too, that declines and advances may refer to single-family homes as well as single-family homes and condominiums. The median price for single-family homes and condominiums fell 1.4% in 2007, slightly less than the drop in the median price for single-family homes only.
And to add further confusion, there are periodic reports about new home sales. The Commerce Department reported recently that new home sales fell by 26% in 2007, which was the steepest drop since 1963, also the first year in which records were kept on new home sales.
If there is a bottom line to this array of housing statistics in their various guises, it may well be that the housing industry is suffering a severe correction with no necessary end in sight.
