THE initial snapshot this week of the nation’s economic output in the second quarter may offer two surprises for the price of one. It may be stronger than expected and weaker than it seems.

A Bloomberg News poll of economists estimates that the economy will have grown at a 3.2 percent annual rate in the quarter, after a tepid rate of 0.7 percent in the first three months of the year. Maury Harris, chief United States economist at UBS Securities, expects 3.8 percent growth but cautions that there is less to that number than meets the eye.

Much of the strength in the second quarter was attributable to businesses rebuilding inventory after they failed to replace enough of the items they sold earlier in the year. Lately they have erred on the side of excess, stocking their shelves too high, and that could lead to subdued growth later in the year, he said.

“The kick you got from a pickup in inventory buying was a one-quarter phenomenon,” Mr. Harris said. “Once you’re back to more orderly inventory replacement, you don’t get good growth in industrial production.”

If consumer spending holds up, it may cushion a decline in inventory building and underpin growth in gross domestic product. But a different component of the report on Friday may suggest that shoppers are taking a bit of a rest.

Real personal consumption, which measures sales after subtracting the impact of inflation, rose at a robust annual rate of 4.2 percent in the fourth quarter and again in the first. Mr. Harris expects a decline to 1.2 percent annual growth in the latest period.

If the figure comes in close to what he expects, the bond market should take the news better than the stock market, he predicted. He asserted, however, that any stock market decline would probably be short-lived.

For Mr. Harris, a softening in consumer spending would confirm an observation made last week by the Federal Reserve chairman, Ben S. Bernanke, that the housing market slump was affecting the broader economy..

“If consumer spending continues to go up at just a 1 percent to 1.5 percent annual rate, you’ve got to blame something,” Mr. Harris said. “It’s not jobs or the stock market, so it must be housing by a process of elimination.”

DATA WATCH No respite for the housing market is anticipated this week. The Bloomberg poll forecasts sales of existing homes to have fallen to an annual rate of 5.87 million units in June from 5.99 million in May; that report is due Wednesday.

A decline is also expected when data on sales of new homes are announced the next day. An annual sales rate of 900,000 is estimated for June, down from 915,000 for May.

One of the more volatile and unpredictable items on the economic calendar each month is orders for durable goods — large household or industrial items with long useful lives. The Bloomberg poll calls for an increase of 1.9 percent for June when the report is released Thursday, compared with a 2.8 percent decline for May. Mr. Harris expects a gain of 2.0 percent.