By AUSTIN NELSON

Existing home sales fell again in October, reversing gains seen in September. The National Association of Realtors, or NAR, released October existing home sales data today, which show decreases in units sold as well as median sale price across the country. The annual price decline was the worst on record, continuing the worst housing slump since  the Great Depression.

Nationally, existing home sales fell a seasonally adjusted 3.1% month-over-month, representing a 1.6% drop from a year ago. In September, sales improved from last fall’s atrocious levels – data the NAR pointed to as a sign of stabilization in the housing market. This assessment appears to have been premature. October’s decline in sales is more in line with the current economic climate of rising unemployment and severe home equity losses.

Sales were down throughout the country:

• Northeast: -1.2% m/m, -9.8% y/y
• Midwest: -6.0% m/m, -9.1% y/y
• South: -3.2% m/m, -10.2% y/y
• West: -1.6% m/m, 37.5% y/y

A few of these numbers are worth singling out.

First, the Midwest was hardest hit, evidencing the fallout from the troubles with the automakers. Second, sales in the West fell, following improvment in September. Again, the NAR had pointed to last month’s gain as an indicator of market health, claiming the West’s markets were showing renewed strength after being the hardest hit to date. The decrease last month shows that this “renewed strength” is typical NAR spin: Even drastic reductions in home prices could not stimulate sales growth in the region.

The figures released on median home sale prices are perhaps even more revealing as to the current state of the housing market.

Nationwide, home prices tumbled 4.2% month-over-month. The largest drop was seen in the West, which saw a dramatic 9.3% decrease. This decline came in the context of a market that had already seen 25% lower home prices than the peak in 2006. Markets in regions that have thus far held up better should expect continued deterioration if they follow a similar trend.

From a “rosier” perspective, this large drop in median price was due at least in part to the paralysis in credit markets over the last two months. The restriction of credit to the private mortgage market dramatically reduced the availability of jumbo loans – which are not backed by the government – preventing buyer’s from bidding on expensive homes.

As a result, the mix of homes sold in October was likely skewed towards the cheaper properties that are available for purchase using loans offered by Fannie Mae, Freddie Mac and the FHA. This concentration of lower priced homes helped push down the broader, median home price data reported by the NAR. As credit markets improve, albeit slowly, this effect should ease pressure on the broad indicators.

Rosier perspective aside, further nationwide declines in home prices and sales should be expected, as  economic conditions continue to erode. However, as the earth-shattering financial events of the past few months play themselves out, it will be important to watch the West as a bellwether of national markets.

The West has led the way in declines thus far, so it is reasonable to look to this area as a proxy for how economic hardships will affect other regional housing markets. Furthermore, as the West has seen the lion’s share of the market pain thus far, signs of true stabilization should appear there first.

Finally, it is important to note that regional economic numbers can conceal even the largest of local trends. Within local Western real estate markets, conditions are widely varied, with some markets only beginning to decline and others beginning to show truly renewed strength.

Only time, and feverishly detailed scrutiny will allow effective market analysis in these unpredictable and volatile times.