Each month we publish the number of sales pairs used in the calculation of the S&P/Case-Shiller Home Price Indices. Data are collected on sales of specific single-family homes or condos. Each sale price is considered a data point. When a home is resold, months or years later, the new sale price is matched to the first price creating a sale pair.
The chart below makes it clear that home sales have slowed down quite a bit over the past three years. The volatility of the graph shows that the housing market does behave with a distinct seasonal pattern. For both the 10- and 20-City Composites, sales volume peak around August of each year (the high points of each line, each year) and are at their lowest around February (the low points). While losing none of the seasonality, you can see the down shift in the peaks and valleys in the data. For the 20-City Composite, sales pairs peaked at no more than 100,000 each August since 2008 and the floors are closer to 60,000; for the 10-City Composite we see 55,000 and 30,000, respectively. In both cases, well below any other years since 2000. Like starts and other sales data, a housing market recovery will be highlighted by an increase in S&P/CS sales pairs.