For the last three years, David Seiders has been talking about the impending slowdown in the housing sector. And he should know. After all, he's chief economist at the National Association of Home Builders.

In the spring of '97, Seiders warned that housing was likely to falter as the Federal Reserve Board began to tighten monetary policy. Then, in the fall, he fretted that the world economic crisis would bring the market to its knees. A year later, it was the Russian debt default that had the economist pulling out his hair. And last year, it was something else again.

But a funny thing happened on the way to the debacle. Growth in the housing sector didn't slow. It actually accelerated. An estimated 2 million units a year have been built since 1997, a level that by Seiders' own admission is well-above demographically-based estimates of sustainable growth.

"And this massive amount of production didn't go into inventory, either," the housing prognosticator also points out. "They all were sold or rented." In fact, the backlog of unsold homes is actually below average.

So, is Seiders now ready to give up the ghost? Not a chance, he says. "A slowdown is coming," he continues to warn, "it's only a question of how soon." And just how soon might that be? "Really soon, perhaps even in the second half" of this year.

The reason: "The Federal Reserve Board cannot be beaten," the NAHB economist explains. "It is bound and determined not to be beaten by the stock market and the resilience of the normally interest-sensitive components of aggregate demand, including housing."

For that reason, Seiders expects the Fed to ratchet up the rate it charges member institutions not once but twice more in the second quarter and twice more again in the third, driving the all-important Fed funds rate to 7 percent.

Since the prime rate banks charge their best customers is usually 3 percentage points above that, if Seiders is on target this time, the prime rate would rise in fairly short order say, by as soon as early October to double digits. And that, the economist says, is "pretty serious money" to builders.

The good news, Seiders also predicts, is that rates consumers pay for their home loans probably won't rise as much, perhaps only about half-a-point, to 8.75 percent by the end of the year.

Nevertheless, he believes that the "added jolt in the interest rate structure, along with some modest negative impacts on consumer and business spending from higher energy prices and lower stock valuations, should be enough to produce the long-awaited downslide in housing market activity."

Even at that, however, production shouldn't falter by much, according to the NAHB's latest figures. Total housing starts for the year will slide only to an annual pace of 1.5 million, which Seiders says is "still very, very good" and "not a matter for tremendous concern." And of that number, 1.2 million will be single-family starts, which the economist insists is "still an excellent, excellent performance."