Leading Indicators Take Sixth Drop in a Row : Economy: A separate report puts construction spending at a four-year low.

The government’s main gauge for forecasting economic activity fell 0.4% in January, its sixth straight drop, but some analysts said the relatively moderate decline signaled a mild recession.

The index of leading economic indicators’ string of declines, which included a revised 0.1% drop in December, matched the six consecutive drops from May through October, 1984, the Commerce Department said. The December index first was reported to have edged up 0.1%.

The index has not advanced since an anemic 0.1% gain last June. It was unchanged in July.

“It is telling us that the recession is not going to be deep because the extent of the declines is not that great,” economist Robert Brusca of Nikko Securities Co. International said of the latest index reading. “It may be heralding a shallow recession.”

“Whether or not this will be the actual trough (of the recession), we are seeing signs of a bottom forming,” said Bob Dieli, an economist with Northern Trust Co. in Chicago.

Gilbert Benz, an economist with the Swiss Bank Corp. in New York, concurred, saying that the index “does project a relatively mild recession.”

Because the index is designed to forecast economic activity six to nine months in advance, Benz said, “we cannot expect any sustained improvement until May or perhaps June.”

Benz said the index would have to fall 0.8% to 1.5% a month to forecast “a relatively severe recession.” During the six-month decline, the index has tumbled an average of just 0.8%.

The Administration, which also projects a mild contraction, agreed. Chairman Michael J. Boskin of the President’s Council of Economic Advisers said after a congressional appearance Friday that “we expect the economy will be rebounding sometime toward the middle of the year.”

Only five of the 11 forward-looking components were positive in January, including an index measuring consumer confidence. Analysts expect this index to improve even more since the Persian Gulf War ended in an allied victory.

Nevertheless, many economists question whether improved confidence will translate into an early end to the recession because of rising unemployment and falling incomes.

And economist Gordon Richards of the National Assn. of Manufacturers said, “There are other factors that will keep the economy in a slump until midyear.”

One of the factors is the construction industry, which posted another decline in January.

The National Assn. of Purchasing Management said its monthly index of business activity indicated that the recession was ebbing. Its index rose to 38.5% last month from 37.7% in January, but was still below 44%--the point at which the association considers the economy to be in a decline.

In a second report Friday, the Commerce Department said construction spending fell 2.6% in January to a seasonally adjusted annual rate of $396.6 billion, its lowest level in four years. It was the 10th consecutive monthly drop.

Still, the Federal Deposit Insurance Corp.’s chairman, L. William Seidman, and several housing industry trade groups have reported anecdotal evidence that the nation’s real estate slump may be bottoming out.

But that was not indicated in January’s leading index. One of the components that often is a barometer of future housing activity, building permits, fell.

The other negative factors were a shorter average workweek, faster business delivery times, a tighter money supply, a drop in prices of raw materials (suggesting slack demand) and lower stock prices.

In addition to the consumer confidence index, the other positive components were an increase in factory orders for consumer goods, a drop in initial unemployment claims, an increase in unfilled factory orders and a boost in orders for new plants and equipment.

The various changes left the index at 139.1% of its 1982 base of 100 and down 4.3% from its level a year ago.