When the Labor Department publishes its latest unemployment figures next Friday, the statistics are expected to show the nation's jobless rate finally beginning to edge up as a result of the economic downturn.

If so, it could renew a longstanding controversy that has plagued the unemployment figures whenever joblessness is high: Do the numbers really provide a complete picture of the impact of the current slump?

To be sure, no one is suggesting that the statistics are being manipulated. An effort by the Nixon administration to inject politics into U.S. statistics-handling was soundly defeated in 1971.

The integrity of the numbers stands unchallenged. But for years, the jobless figures have been criticized either for not including all out-of-work Americans or for failing to measure accurately the extent of their hardship.

Members of Congress -- particularly those from hardpressed northeastern states -- also have complained bitterly that the figures understate the actual unemployment picture in their areas.

Black groups -- and many labor leaders -- contend the figures don't take enough account of job-seekers who have become discouraged and simply drop out of the labor force. Conservatives argue that teenagers shouldn't be included.

There have been frequent calls for overhauling the entire statistics-gathering process.

The issue is important because the figures are crucial to two critical government functions: They form the basis for economic policymaking, and they often determine the size of grants to states and localities.

In either case, they affect billions of dollars in federal spending. The typical congressional tax cut these days runs about $20 billion. And the unemployment data affects about 10 billion in federal grants.

In 1976, faced with just such pressures for altering the jobless data, Congress established a blue-ribbon commission to review the unemployment figures and make recommendations for any changes it might feel were needed.

Now, after months of hearings and deliberations, the nine-member National Commission on Employment and Unemployment Statistics has issued a final report that, if anything, should startle critics of the jobless figures.

Although the panel made 88 separate recommendations for changes, some of which are likely to prove controversial, it essentially found no fault with either the accuracy or the scope of the existing statistics.

Sar A. Levitan, a longtime manpower activist who headed the 1 1/2-year effort, conceded the commission had urged "a minimum amount of change" partly because it believed that more sweeping recommendations would not be taken seriously.

But Levitan added that "it would have served no purpose if we had recommended a wholesale revamping" of the current data because the existing system may not be perfect, but it isn't that badly flawed.

The commission did deal with some long-criticized inadequacies:

In response to congressional complaints that current figures too often understate local unemployment problems, the commission recommended expanding the Labor Department's monthly survey and standardizing state jobless measures.

Under present procedures, government survey-takers question 40,000 households each month to obtain a sample on which to base the national unemployment figures. Next month, that will be expanded to 70,000 households.

The commission recommended enlarging the sample still further, to 110,000 households, and urged some technical changes to improve both the federal sampling techniques and state and local statistics-gathering.

But it warned the lawmakers it would be too costly and impractical to provide more detailed state and local unemployment figures. It urged the lawmakers instead to revamp federal formulas for allocating grants.

The panel rejected the demand by liberals that the figures be revised to count so-called "discouraged" workers formally as part of the monthly labor force report -- on grounds that it is too difficult to tell whether they really are seeking work.

The commission also turned down a proposal by conservatives that the government exempt most teenagers from the unemployment statistics by raising the minimum age at which persons are counted from the present 16 years.

Those seeking the change had argued that most teenagers are interested only in part-time work, and so including them in the figures only blows the problem out of proportion. At 16, teenagers no longer are required to attend school.

The panel recommended including military personnel in the count of employed workers, on grounds that, under the new "volunteer" armed forces, the military is as much a regular "job" as most civilian occupations.

However, it urged that the change not be extended to state and local jobless figures. The reasoning: Military personnel stationed in a locality most likely are from out of town, and not part of the area's actual work force.

And perhaps most significantly, the commission recommended publication of a new annual report on the actual economic hardship imposed on American families by given levels of unemployment.

The panel pointed out that the level of unemployment no longer serves as an accurate indicator of hardship because of the increase of two-earner families, government welfare and unemployment benefits and other factors.

At the same time, however, the commission stopped short of proposing that officials develop a new index to measure economic hardship, as some liberals had suggested. The report would be prepared by the Bureau of Labor Statistics.

The panel estimated that its 88 formal recommendations -- most of them technical and not involving broad policy questions -- would cost about $34 million a year to put into effect.

But Levitan cautioned that implementing all of the panel's suggestions wouldn't alter the unemployment rate significantly. At most, the current 5.7 percent rate might go "up or down" by two-tenths of a percentage point.

Perhaps even more interesting than the recommendations that the panel actually made, however, were the issues that it skirted -- most of them major policy questions about which controversy is almost certain to continue. Among the issues the panel side-stepped:

What should the government recognize as "full employment" -- the lowest unemployment rate that the nation can achieve through broad management of the economy without exacerbating inflationary pressures?

In the mid-1960s, that rate was accepted as about 4 percent, but in recent years, with a growing proportion of women and teenagers in the labor force, it's been boosted -- informally -- to between 5.5 percent and 6 percent.

What should the government do about youth unemployment? There's continuing controversy over how bad teenage unemployment actually is, and whether the government ought to do something to combat youth joblessness.

Although a high proportion of teens are listed as jobless, Labor Department figures show their actual number is relatively small. Moreover, many teenagers quit their jobs after only a few weeks. Should they even be counted?

How should the government try to measure economic hardship? The commission discussed several proposals for a new index, but found its own plan unworkable. The question still is unresolved.

The panel's latest effort constitutes the first major review of the nation's unemployment figures since the now-famous Gordon Commission report of 1961.

As Levitan himself conceded, many of the current ways of measuring joblessness were established in the 1930s, when the economy -- and the government's needs for figures -- were far different.

As it stands now, a Labor Department task force will review the panel's recommendations and then send them on to the White House and to Congress. Changes, if any, are apt to be months away.

Still, the fact that the panel recommended such modest changes was taken as bolstering the view by experts in the field that, for all the year-to-year controversy, the statistics aren't bad ones.