Mark Sprague Explains Case-Shiller

The Case-Shiller index has reported home values for nearly 30 years. The index has become a widely reported and analyzed measurement of the housing market, looking at home values of repeat sales in particular. It is commonly referred to by the media, especially as the index has dropped in recent years. Few, if any, other statistics are more watched than the Case-Shiller by those in the housing industry. 

And, yet, it contains some flaws and limitations, according to Mark Sprague, Director of Business Development at Mission Mortgage.  Among Sprague’s concerns are the relatively small sample size and that it only looks at repeat sales, taking new homes, condos, and multi-family units out of the mix.  Mostly, though, the measurement is limited due to the fact that what it implies does not exist – there is no such thing as a national real estate market.

Recently, Mark put into words his opinion of the Case-Shiller index and why he believes it should be given less weight by the media. While he doesn’t expect his thoughts to bring radical change to the way the housing industry is covered by the press, he does hope that bringing out this information will help realtors, builders, investors, and others to understand what the index means and to whom it is important.

Here’s what Mark says about the Case-Shiller Index:

Mark Sprague, Mission Mortgage of Texas

First, remember there is no such thing as a national Real Estate market. All real estate is local. No matter what the Case-Shiller Index says about the country, what matters to your local market is what’s happening in your local market. Each neighborhood has its own housing economy and that’s something that can’t be captured by a national report. A sale in Detroit does not affect a sale in Austin……..

As a buyer / observer in today’s market, though, you can’t take the Case-Shiller Index at face value. It’s methodology is far too flawed to be the “final word” in home prices:

The first big Case-Shiller Index flaw is its relatively small sample size. S&P positions the Case-Shiller Index as a national index but its data comes from just 20 cities total. And they’re not the 20 most populous cities, either. Notably missing from the Case-Shiller Index list are Houston (#4), Philadelphia (#5), San Antonio (#7) and San Jose (#10). Minneapolis (#48) and Tampa (#55) are included, by contrast.*  This means that most U.S. home sales are not included in the Case-Shiller Index’s monthly findings.  Case Shiller tracks 20 markets that had and have high regulatory parameters, causing values to be artificially high in those areas, causing speculation for a limited number of units.

  • A second flaw is that it doesn’t measure supply or demand.  A true measure of any product. Over 50% of the cities are not forecast as growth areas by the Census.  Homes in the wrong place at the wrong time. Supply and Demand imbalances are the ultimate driver behind real estate prices, and local, regional as well as national data shows the balance is improving, with months of resale supply recently declining from 12 to 10 months nationally and much less here locally.. Normally, those inventories are approximately seven months, and until the overhang of unsold homes is reduced, prices will not recover.
  • Another Case-Shiller flaw is how it measures a change in home price. Because the index throws out all sales except for “repeat sales” of the same home, the Case-Shiller Index fails to capture the “complete” U.S. market. It also specifically excludes condominiums and multi-family homes. In some cities — such as New York, Chicago — homes of these types can represent a large percentage of the market.
  • Another limitation is that the Case-Shiller Index is on a 2-month delay. It’s June and we’re only now getting home data from March. The Case-Shiller Index is far less useful than real-time data of a city or neighborhood.
  • The Case Shiller index relies exclusively on transactional data from home sales, a flawed methodology since less than 0.5% of homes are sold each month. That is too small a sample size from which to make broad conclusions about the national housing market,
  • The biggest problem with Case Shiller is that current market transactions are not representative of overall market trends.

I have a great amount of respect for Dr. Shiller and his predictions.  I obviously don’t have an index named after me, so I am not poking holes at Dr. Shiller. However there are better indices to follow (Altos mid cities composite is a good one, and for Texas the Texas A&M Real Estate Center).  However the best indice is true measurement of your individual neighborhoods by your local realtor, gauging supply and values, demand will be apparent soon enough. 

Keep focused on how good your market is.   The media quotes Case-Shiller without really understanding it – the national market supply and demand, particularly in Texas and Austin.

* This is the list of the 20 cities tracked in the main Case-Shiller Index, in alphabetical order:  Atlanta, Boston, Charlotte, Chicago, Cleveland, Dallas, Denver, Detroit, Las Vegas, Los Angeles, Miami, Minneapolis, New York, Phoenix, Portland, San Diego, San Francisco, Seattle, Tampa, Washington D.C.

Mark Sprague is a respected real estate analyst who provides local expertise along with statewide and national market knowledge. He produces a weekly online newsletter called The Mission Statement where he looks at a vast array of topics that influence the overall housing industry. If you would like to hear more from Mark, be sure to sign up for the newsletter at

About missionmortgage

A full-service professional mortgage banker providing lending in Texas for over 25 years. Our main office is located at 901 S. Mopac Expwy, Barton Oaks V- Suite 120, Austin, TX 78746 with branches in Lakeway, Houston, and Sealy. Mission Mortgage has been ranked as a Top 10 Mortgage Company in Austin for the past 7 years (Austin Business Journal).
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