Sears, Roebuck & Co. yesterday reported that it sold less goods but made more money in the final three months of 1978 and said these results show the company's new operating philospophy is working successfully.

That analysis was greeted skeptically on Wall Street, where retail-industry specialists said Sears' earnings are still below par and the success of Sears' new strategy won't be determined for several months.

Sears decided last year to try to improve its profit margins by reducing advertising and the amount of price cutting, even if that meant fewer sales.

The sales and profit figures reported by the nation's biggest retailer yesterday gave some indication that the new philosophy is working.

For the fourth quarter, Sears said its net earnings jumped by 31 percent to $329.9 million ($1.02 a share) from $251.8 million (78 cents.) Sales declined from $4.99 billion to $4.93 billion.

For the year, Sears earned $921.5 million ($2.86), up from $837.9 million ($2.62), and sales increased about 4 percent from $17.22 billion to $17.95 billion.

Despite the improvement, Sears still made more money from its Allstate insurance companies than from its retail stroes. Allstate produced $465.6 million of Sears $921.5 million profits, and other subsidies earned another $100 million.

The $356 million that Sears made on its vast retailing empire "is not a satisfactory porfit margin," said Margaret Gilliam, who follows Sears stock from First Boston Corp.

She said there was evidence in the third quarter that Sears' retail business was making more money, but noted that the $1.10 a share earned by the stores was below the expectations of many analysts.

Analyst Daniel Barry of Kidder, Peabody & Co. said Sears' earnings "were not quite as good as I predicted," and said it could take several more months to see whether Sears' chief executive, Edward Telling, has redirected the company successfully.

Walter Loeb of Morgan Stanley, noted that evaluating Sears' sales performance is difficult because the company's sales a year ago were bloated by unprofitable promotions. The first six months of 1979 will determine whether Sears merely has eliminated that unprofitable business or is boosting its basic profit margins, Loeb said.