Economists can nitpick over statistics but, for Eugene Scott, 35-year-old black Baltimore construction worker, the government's massive and controversial public service job program is a success.

Scott came from a family of 14 children and never finished high school. He had to quit to help support the others. He held a succession of intermittent, low-paying jobs - "syrup man" at Coca-Cola at $2.15 an hour, maintenance painter for a steel company, carpenter's helper for a construction firm that went out of business.

In 1976, out of work for months and down on his luck, he walked into the City Baltimore's Homewood man-power office. He landed a federally funded public service job with the local housing department at $4.70 an hour, repairing houses for low-income older people and keeping public housing up to snuff. He learned how to paint better. He worked at drywall and plastering. He started taking nightschool classes sponsored by the program to get his high school equivalency diploma.

He did so well that on May 1, 1978, he landed a regular, full-time city job at $5.05 an hour. "It's a permanent job," said Scott in an interview at Baltimore's remote Cherry hill public housing development, where

"This is a lucky blow for me goget with them. . . .

"It gives the small guy a chance. You got some guys there who really work. One fellow there named George Freeman, he really liked to work; during lunchbreak he kept working."

Success tales like Scott's, repeated for thousands of workers, are the main reason Congress and President Carter are getting ready to provide about $11 billion next year to continue 725,000 federally funded public service jobs, over 1 million job-training openings and hundreds of thousands of summer youth jobs.

What's more, these programs, which fall under the umbrella of the Comprehensive Employment and Training Act (CETA), have embedded themselves into the national economy despite allegations of scandal and continuing disagreement among experts over their actual worth.

Municipalities and counties like CETA because it adds to the local government workforce without draining tax resources. In some communities, CETA employes make up 15 to 20 percent of local government payrolls. Some large cities are now virtually addicted to CETA and would fight any attempt to eliminate it, even though many of the jobs were funded orginally as a mid-1970s antirecession move.

Others also believe in the program, from Democrats in Congress to minority spokesmen to labor unions to Labor Department officials, which is why the CETA reauthorization seems in no trouble as it moves through Congress.

Nevertheless, CETA's overall economic value is under severe challenge.

Some economists believe that as many as perhaps 70 percent of the public service jobs simply substitute for jobs the cities and counties would have filled anyhow with their own money. But Ernest Green, assistant secretary of Labor for employment and training, says recent studies show it may be as low as 18 percent.

Other economists say much of the work performed by CETA employes may be of little value akin to the famous 1930s WPA project in Franklin D. Roosevelt's administration on the history of the needle.

There are also substantial questions about how many people passing through CETA training obtain jobs as a result. The evidence is skimpy.

The Labor Department's own figures show that only about one-third of those leaving CETA get non-subsidized jobs immediately. However, others find jobs later.

Green says a new study shows that, in one national sample, 58 percent of those leaving CETA training or job slots were in non-subsidized jobs within three months. But no one is certain whether this is a result of their CETA experience or whether they would have obtained such jobs anyhow.

While the jobs program has expanded unemployment has fallen from 8.5 percent in 1975 to 6.1 percent in May 1978. But economists aren't certain what role CETA has played.

Some economists believe the money would be better spent on tax breaks for businesses and individuals that would spur new business investments. CETA is also criticized for not targeting its benefits adequately on low-income persons and minorities.

The government has had manpower training and public job programs for years. But CETA in its current form was first authorized in 1973. It has two major components: training and employment service (Title 1), for which the government spent $1.9 billion in fiscal 1977, providing services to 1.4 million persons: and public service jobs, which provide 725,000 slots annually at a cost of more than $6 billion.

CETA also includes special youth programs, the Job Corps, summer youth jobs and positions for seasonal workers and Indians: these cost less than $1 billion combined.

The training and PSE jobs are run by 445 cities, states and large counties called "prime sponsors."

The program's image has been tarnished by a series of scandals in which clubhouse politics rather than objective eligibility determined who got jobs.

In East St. Louis, for example, jobs were dispensed through a city personnel director who was also a political precinct committeeman, and the Labor Department found 36 such precinct committee members and 21 relatives of aldermen or city officials on the CETA payrolls.

In Chicago, about 75 persons were alleged to have received CETA jobs as a result of "political referral letters" though most were otherwise eligible. Similar charges were made in several other cities.

To prevent waste and misuse of funds, the pending legislation requires prime sponsors to submit detailed long-term master plans and annual plans for CETA projects to the Department of Labor, and to stick to them. Labor Secretary Ray Marshall has already established a 200-person office to investigate waste and fraud in all department programs, including CETA. The new legislation also proposes an office of audits, inspection and compliance to monitor CETA programs.

In addition, the legislation requires most PSE jobs to be in separable projects of limited duration (usually a year), rather than integrated into the basic local government labor force. The purpose here is to reduce the possibility of illegally substituting federal dollars for state or local dollars without providing additional jobs.

Such substitution is forbidden by the law. But it is difficut to prove Studies by the Brookings Institution have concluded that the substitution rate is between 18 and 30 percent. An ongoing National Academy of Sciences study that began in late 1974 has estimated substitution at about 35 percent. Both figures are far lower than assumed earlier, but still are not universally accepted.

Economists also don't know just how much CETA's public service jobs help the overall economy.

A recent study by the National Commission on Manpower Policy concluded that $1 billion spent on public service jobs created about $2 billion in gross national product - about the same as other types of government spending or tax cuts - but creates substantially more jobs and may be less inflationary.

That view is widely held in the economic community, but it does not answer the question of whether the jobs provided are "useful." The Brookings study concluded most were not simply make-work, but critics say many of the jobs - Baltimore's "pooch patrol," which cleans up after dogs, for example - are of marginal value.

Another criticism of CETA especially the public jobs program is that it doesn't lead to legitimate private employment for participants.

But new figures from the Labor Department show that 58 percent of persons who early in 1975 were in the CETA program - public jobs or training - had nonsubsidized jobs three months after leaving CETA. The figure nine months after had risen to 62 percent. And figures on employment a year after leaving are even more impressive - 73 percent for on-the-job training graduates 65 percent for public service jobs workers.

There is also debate over whether CETA actually focuses on the poorest workers - or even whether it should.

Orginally, the law did not restrict public service jobs to low-income persons. Some economists and politicans believe it should continue along those lines, but the Carter administration proposes that it be narrowly targeted on low-income persons. Congress seems inclined to go along.

Statistics developed by the Manpower Commission show, however, that low-income persons have received a majority of the CETA siots, far more than their share of total unemployment.

But it is the experience of people like Baltimore's Eugene Scott, painter, plasterer and drywall man: that ultimately creates the climate of political acceptance that feeds the CETA program.

That is why, regardless of economic conditions and experts' debates, the massive attempt at job-creation may continue to grow.