Case-Shiller: Phoenix Home Prices Decline Slightly Again in March

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 (requires free registration). 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. – March data is released in May).

Here are the basic Case-Shiller stats for the Phoenix area* as of March:

March 2010
Month to Month: Down 0.5%
Year to Year: Up 2.4%
Prices at this level in: June 2001
Peak month: June 2006
Change from Peak: Down 51.8% in 45 months
Low Tier: Under $110,734
Mid Tier: $110,734 to $180,906
Hi Tier: Over $180,906

Fourteen of the twenty metro areas tracked by Case-Shiller saw an decrease in their respective HPIs between February and March (vs. 19 January to February). Cleveland, San Francisco, San Diego, Denver, Dallas, and Seattle all saw increases, ranging from just 0.1% in Seattle to a whopping 2.4% in Cleveland.

Here’s a look at Phoenix’s latest 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:


All three tiers in Phoenix dropped in March, with the middle tier falling the most—down 0.6%. The low tier fell 0.1%, and the high tier was down 0.5%.

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.


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


San Diego is still posting price gains, and San Francisco bumped up again, but everywhere else was either down or basically flat in March. Looks like we may not get a second bounce as the homebuyer tax credit expires for real this time.

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. – March’s index represents the average of the data from January through March).

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 Phoenix as the Phoenix-Mesa-Scottsdale, AZ Metropolitan Statistical Area, which includes all of Maricopa and Pinal counties.]