Case-Shiller: Home Prices Dipped Across the Board in October

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. – October data is released in December).

Here are the basic Case-Shiller stats for the Boston area* as of October:

October 2010
Month to Month: Down 1.2%
Year to Year: Down 0.2%
Prices at this level in: July 2003
Peak month: September 2005
Change from Peak: Down 15.4% in 61 months
Low Tier: Under $271,274
Mid Tier: $271,274 to $417,467
Hi Tier: Over $417,467

All twenty metro areas tracked by Case-Shiller saw a decrease in their HPI between September and October (vs. 18 August to September). Only four markets posted year-over-year gains: San Francisco, San Diego, Los Angeles, and Washington DC.

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

Bos-Case-Shiller-Tiers_2010-10

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

Bos-Case-Shiller-Tiers_2010-10

Pretty much an even spread of losses across all three tiers this month. Month to month, the low tier was down 1.1%, the middle tier fell 0.9%, and the high tier decreased 1.4%.

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

Case-Shiller-Redfin-Markets_2010-10

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.

Case-Shiller-Peak-Declines_2010-10

Here’s the flip side of the peak decline chart—a graph since January 2009, indexed to January 2009 = 100%:

Case-Shiller-2009-Bounce_2010-10

With the post tax credit home price double dip now in full effect across the board, I think it’s about time to retire this last chart.

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 Boston as the entire Boston-Cambridge-Quincy, MA-NH Metropolitan Statistical Area, which includes all or part of the following counties: Essex MA, Middlesex MA, Norfolk MA, Plymouth MA, Suffolk MA, Rockingham NH, and Strafford NH.]