Toward the latter part of every month--normally between the 23rd and the 28th--two important housing reports are issued. These are data on sales of new homes and existing residences. The source for the former is the U.S. Commerce Department; the figures for the latter are supplied by the National Association of Realtors—a private group.

These reports are clearly different and should not be confused with other indexes, such as that on pending home sales. The figures are estimates, with a range of error, and are always expressed on an annual basis. At its peak, the new home sales market was close to 1.5 million units annually; re-sales were upwards of seven million units per year.

Essentially, the report on new home sales gauges activity across four geographic locales: the Northeast, the Midwest, the South, and the West. Its categories include single-family dwellings (the largest individual sector) and multi-family units, such as apartment buildings. Obviously, the size of the market depends on the locale measured, with multi-family units a greater percentage of aggregate activity in the Northeast than the less-urban South, for example.

For sales of existing homes, we need to consult the National Association of Realtors. This group measures re-sale activity. It is a far larger and less volatile market than sales of new homes. The comparative stability in this sector has meant that re-sale activity has generally stayed between five million and seven million homes per year. By comparison, new home sales have ranged from about 300,000 units on an annual basis up to 1.3 million. As with new homes, this category is chronicled for the Northeast, the Midwest, the South, and the West.

These reports also measure housing prices and inventories of unsold homes, two critical variables in this important consumer market. Commentary, which is often useful, accompanies these reports, and is a worthwhile tool in assessing the trends put forth by the data.