Retail sales climbed a modest 0.2 percent in November, the Department of Commerce reported yesterday, a further sign that the economy may be slowing down.

The sales figures provided the first official glance at the strength of consumer spending since the stock market collapse in mid-October. With consumer spending accounting for nearly two-thirds of the economy, retail sales are critical to the nation's future growth.

The latest results of consumer spending came on the same day the government disclosed that producer prices remained steady last month -- meaning that inflation is not a serious threat for the foreseeable future.

Despite the modest sales increases reported for November, most economists were heartened by the latest numbers, which showed consumers spent $125.9 billion at retail establishments last month -- $210 million more than in October.

"I think the retail sales report is relatively optimistic in a perverse sort of way," said John Hagens, vice president of economic services for the economic consulting group WEFA. "The numbers are not dreadfully down so that the reaction by consumers to the drop in the stock market in October doesn't look like a catastrophe for retail sales.

"The numbers are also good because sales are not absolutely booming, with consumers ignoring the drop in the stock market. Had that happened, that would have indicated that the {market} drop was not enough to slow demand, which is the key to gradually turning around the trade deficit," Hagens added.

However, economists noted that they were concerned about the Department of Commerce's revisions to the retail sales numbers recorded for September and October. For both months, Commerce said sales fell more than it had initially predicted. It revised October sales from a decline of 0.2 percent to a 0.9 percent drop from September. Sales in September dropped even more, by 1.7 percent from August instead of the 1.1 percent drop previously reported.

"Since September, retail sales actually have declined by a full percent over the previous three-month period," said Richard W. Rahn, vice president and chief economist for the U.S. Chambers of Commerce.

Economists said that although consumer spending may have been slowed by the stock market crash, it had slowed sharply before mid-October. As a result, they predicted continued sluggish growth.

"I think you can expect retail sales to plummet after the first of the year as consumers seriously get back to the retrenching they started in September," said Jerry Jasinowski, executive vice president and chief economist of the National Association of Manufacturers.

"Consumers are not going to carry the economy in 1988," said Robert Ortner, undersecretary of Commerce for economic affairs. "We will have to count on capital spending and exports."

The Department of Labor reported that the producer price index for finished goods remained the same in November, following a 0.2 percent drop in October. For the 12 months from November 1986 to last month, producer prices for finished goods were up 2.5 percent.

Producer prices on intermediate goods -- those used by manufacturers to make finished products -- jumped by 0.4 percent last month, while prices for crude goods dropped by 1.7 percent -- the second decrease in three months after climbing the first eight months of the year.