Stockroom shelves post new gain, but this time it's not tied to torrid economy

After giving the economy a strong push-off earlier this year, inventory growth has now hopped on for the ride. Data released by the Department of Commerce this week don't show that, but a number of economists hold to it.

''We're now on the downshifting phase of the cycle, where inventory is not adding to the overall growth rate (of demand for goods), but just complementing it,'' says Joseph Carson, senior economist at Merrill Lynch, Pierce, Fenner & Smith.

''Inventories are pretty much a neutral factor at this point,'' agrees Edwin Warren, an economist at Chase Econometrics in Bala-Cynwyd, Pa.

The latest inventory figures show stronger gains during July than expected. Manufacturing inventories were up 0.9 percent and wholesale inventories up 1.8 percent from June - both notable increases compared with growth in the previous few months. Inventory buildup is a driving force in a recovery as manufacturers anticipate demand and then stock up to meet it.

But the ''July blip,'' as Mr. Warren calls it, is misleading. More goods sat on stockroom shelves in that month because sales declined, not because manufacturers were gearing up for a new spurt in demand.

''A large portion of the July inventory may not have been entirely wanted and anticipated'' by manufacturers, says Jill Thompson, senior economist at Data Resources Inc., a consulting and research concern in Lexington, Mass. Industry was surprised by the 0.8 percent decrease in July sales, the first setback in five months. The sales drop ''was very substantial,'' she says. ''It seemed to occur across manufacturing, wholesale, and retail.''

Not all businesses were stuck with more goods in the back room than they wanted. The auto industry still hasn't been able to produce enough to meet demand, and if the auto strike continues, the situation will become worse. ''They may have tried to build inventory,'' says Mr. Warren at Chase, ''but they haven't been very successful because demand has been so strong.''

On the retail side, inventories in July actually dropped 0.2 percent, the second monthly delcine in a row. (The figure is seasonally adjusted and takes into account Christmas buying.) Miss Thompson, at DRI, says that the falling off was mainly due to the auto sector and that inventories in soft goods, such as apparel, ''look bloated.''

Retailers will work through that inventory with discounts and sales, Miss Thompson believes. Mr. Carson, at Merrill Lynch, does not agree that such price cuts are likely. ''The consumer still has enormous buying potential to fuel spending in the fall and winter months,'' he says. An article in the New York Times this week pointed out that while retailers had a slow month in July, fall business looks strong.

The July inventory leftovers, heaped on a plate with other economic indicators, feed the idea of an economy growing more slowly. Miss Thompson points out, though, that manufacturers have begun adjusting to the new pace by keeping a lid on orders in May and June and slowing production growth substantially in August.

''This implies that production will slow further,'' she says, explaining that in this quarter ''inventory accumulation will be somewhat smaller'' than last quarter. Since it's the change in the rate of accumulation that affects the gross national product (GNP), she thinks inventories this quarter will be ''either neutral or a slight drag'' on GNP growth.

Economists are mixed on what they think manufacturers, retailers, and wholesalers will be doing in the coming months. ''We expect inventory growth to slow more so in 1985 because we are expecting interest rates early in the year to go up.'' High interest rates and low inflation make keeping inventory expensive.

On the other hand, Mr. Carson says that ''there is still lots of momentum in the economy,'' and he expects inventory will be building in the first quarter of next year.

In either event, inventory building is not like it used to be. Historically, inventories today are much lower. Managers learned from the last recession not to get caught with lots of inventory before an economic downturn.