It has been five years since Congress voted to make Individual Retirement Accounts available to most Americans, and to all outward appearances, the program is a roaring success.

At the end of last year, the total value of IRAs amounted to $200 billion, up from $132.1 billion the year before, according to the Investment Company Institute, a trade association for mutual funds.

IRAs, along with Keogh retirement plans for self-employed people, are expected to draw $40 billion to $50 billion in new money this year, the Employee Benefit Research Institute (EBRI) estimates.

Declining interest rates and record stock averages have made competition fierce this year between depository institutions, the traditional keepers of retirement funds, and brokerages and mutual funds, which are rapidly gaining market share. By yearend, brokerages and mutual funds, which had 10 percent of the market in 1981, are expected to have captured 35 percent of what could amount to $300 billion in IRA and Keogh retirement plan assets, according to EBRI's president, Dallas Salisbury. That compares with $222 billion at the end of 1985.

But while the scramble for dollars and last-minute tax deductions intensifies, some economists and legislators are having second thoughts. Popular as they are, are IRAs also good for the country? Do IRAs increase personal savings, and if so, is the increase enough to offset the lost tax revenue and consequent increase in the deficit? Do they provide an effective retirement cushion for those who need one, or are they mainly a tax dodge for the well-to-do?

Much of the evidence that emerges from the early years of IRAs provides ammunition for critics:

*Most IRA contributors are high-income people seeking tax deductions rather than the less affluent who are not covered by other pension plans.

*The national savings rate has declined since 1981, indicating IRAs have not created substantial new savings.

*The amount of money in tax-deferred IRAs has resulted in revenue losses eight times greater than anticipated.

Indeed, both the House and Senate, mindful of the abuses and economic drawbacks associated with IRAs, are at work reforming and reducing these popular tax-deferred accounts. The tax-reform bill approved by the House would effectively restrict contributions to IRAs while favoring another type of tax-deferred savings plan known as a 401(k) plan.

Under the bill the total contribution to the two plans would be reduced to a maximum of $7,000 per person from as much as $30,000. EBRI estimates that more than $111 million in total retirement savings might have been lost if the House measure had been in effect in 1982.

It was in 1981 that Congress, as part of a sweeping tax reduction bill, extended to all workers the right to have an Individual Retirement Account. At the same time, it increased the maximum contribution to $2,000 annually for individuals, $4,000 for two working spouses, and $2,250 for married couples with one working spouse.

Based on experience with limited IRAs, which had been available since 1974 only to workers not covered by an employer pension plan, experts expected that only about 4.6 percent of the population would set up IRAs. Today, however, approximately 20 percent of American workers contribute to IRAs, and 30 percent have contributed at one time or another, according to Internal Revenue Service figures.

However, data compiled by EBRI show that 11 percent of those persons not covered by a company pension or a newer kind of employer-sponsored tax-deferred savings plan known as 401(k) plan have IRAs. On the other hand, 20 percent of those covered by pension or 401(k) plans have IRAs.

Also, EBRI found, 58 percent of those with incomes of $50,000 and more have IRAs. By comparison, 8.5 percent of those earning between $10,000 and $15,000 have IRAs.

"The IRA is the best savings vehicle in a long time," said Rep. J. J. (Jake) Pickle (D-Tex.), one of the sponsors of the legislation. But even Pickle admits it's time to review the IRA.

The IRA was designed as a supplement to Social Security in retirement, but it appears that those who are now most dependent upon Social Security will continue to be. Meanwhile opinion surveys by the IRA Reporter, a newsletter, show that most wealthy IRA contributors are mainly interested in the tax deduction, not retirement income.

Moreover, the character of the investment appears to be changing. In the minds of the framers of IRA legislation, it was supposed to be conservative, a fall-back reserve. "The purpose was not to encourage gambling," said Barber B. Conable, the former New York congressman who was the ranking minority member of the House Ways and Means Committee.

The Investment Company Institute notes that self-directed and mutual fund IRAs held 30.5 percent of IRA assets last year, up from 23.6 percent the year before. On the other hand, the share held by depository institutions and life insurance companies -- typically offering more conservative, fixed-income investments -- dropped from 76.4 percent between them to 69.4 percent.

The Internal Revenue Service prohibits only a few types of investments, notably collectibles or one's own residence or business. That leaves a broad range of vehicles. Thus affluent people can play the market with help from the government: Their initial ante is tax-deductible, and whatever winnings they run up are shielded from the tax man until retirement.

Another congressional goal was to stimulate savings through tax deferral. Aggregate personal savings last year amounted to 4.6 percent of disposable income, down from 6.7 percent in 1981. Studies on the role of IRAs in stimulating savings show results ranging from a 25 percent increase to almost no impact.

The Federal Reserve Bank of New York concluded that people were transferring their savings from other assets into IRAs. This thesis is borne out by two recent studies showing that retirement funds represent a larger portion of private savings, even though total savings may not be up. And the U.S. League of Savings Institutions reports that 29 percent of savers questioned said they were putting money away for retirement, up from 17 percent three years ago.

Early promoters of IRAs cite increased retirement savings as proof that the original goal of IRAs has been achieved. "I believe that outweighs any cost to the government," said Pickle. Conable named other original social goals such as stabilizing the shaky thrift industry that he felt made IRAs successful.

But as for the overall value to the economy, Conable said, "the jury is still out."

The government calculations that predicted 4.6 percent of eligible Americans would establish IRAs also forecast that the revenue loss to the government from IRAs would be $2.6 billion by 1986. The 1987 budget projects that loss at $21.1 billion, plus another $3.7 billion from Keogh plans.

Of course, that money will be recaptured when people withdraw their funds and pay taxes on them.

The question is how long a government, burdened by deficit, can afford to wait. " Pickle said he favors an in-depth congressional study: "I don't say we should stop IRA growth , but let's take a good look and see what's the best approach."