Case-Shiller: More Home Price Drops as 2011 Kicks Off

It’s time for our monthly check-in of the S&P/Case-Shiller Home Price Indices (HPI). The Case-Shiller data is generally considered to be the most reliable measure of overall home price changes for a region, since they only consider repeat sales of homes when calculating their index, instead of looking at all the homes that sold in a given month.

For the full source data behind this post, hit the S&P/Case-Shiller website. For a more detailed explanation of how the Case-Shiller Home Price Index is calculated, check out their methodology pdf. Also remember that the data released on the last Tuesday of a given month is for the period two months prior (i.e. – January data is released in March).

Here are the basic Case-Shiller stats for the Atlanta area* as of January:

January 2011
Month to Month: Down 0.4%
Year to Year: Down 7.0%
Prices at this level in: November 1999
Peak month: July 2007
Change from Peak: Down 27.0% in 42 months
Low Tier: Under $122,169
Mid Tier: $122,169 to $222,233
Hi Tier: Over $222,233

Nineteen of the twenty metro areas tracked by Case-Shiller saw a decrease in their HPI between December and January (the same as November to December). Washington DC’s tiny 0.1% increase was the only month-to-month gain.

Here’s a look at the latest local tiered data, back through 2000:


And here’s a closer look at the recent changes, with the vertical and horizontal axes zoomed in to show just the last year:


While the low and middle tiers lost considerable ground in January, Atlanta’s high tier actually inched up slightly. Month to month, the low tier was down 2.0%, the middle tier fell 2.3%, and the high tier increased 0.2%.

Here’s a chart of Case-Shiller HPIs for all the markets that Redfin serves:


Here’s our peak decline chart, in which we line up the peak Case-Shiller HPI value for each of Redfin’s markets, so we can see how long each market has been declining, and how much it has dropped from the peak.


Eleven of the twenty cities tracked by Case-Shiller hit another new post-peak low as of January. So far Los Angeles, San Diego, San Francisco, Denver, Washington DC, Boston, Minneapolis, Cleveland, and Dallas are still above their 2009 lows.

Methodology: The Case-Shiller index tracks price changes in sets of homes of similar size and style to better determine changes in what people are willing to pay for the same home over time. If data is available from an earlier transaction for the same home, the two sales are paired and treated as a “repeat sale.” Repeat sales that are too far apart, sales between family members, lot splits, remodels, and property type changes (e.g. from single-family to condos) are excluded from the calculations. All remaining repeat sales are totaled together and weighted based on the time between each sale, then the data for the most recent three months is averaged together to create a given month’s index value (i.e. – September’s index represents the average of the data from July through September).

The three price tiers plotted in the charts below simply represent the top, middle, and bottom third of all sales, based on the initial sale price. In other words, if there were 3,000 sales in the three-month period, 1,000 of them would be in the low tier, 1,000 in the middle tier, and 1,000 in the high tier, by definition.

*[Case-Shiller defines Atlanta as the Atlanta-Sandy Springs-Marietta, GA Metropolitan Statistical Area, which includes all of the following counties: Barrow, Bartow, Butts, Carroll, Cherokee, Clayton, Cobb, Coweta, Dawson, De Kalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Haralson, Heard, Henry, Jasper, Lamar GA, Meriwether, Newton, Paulding, Pickens, Pike, Rockdale, Spalding, and Walton.]

  • Atlanta buyer

    Hi Tim, this blog is great in terms of the Case-Shiller numbers. Can you correlate a bit with what Atlanta Redfin data is showing, that is which neighborhoods have more movement, interpretation on why the upper tier has stabilized, etc. I saw some that being done for other cities.