"He's not changed his economic policies since he took office," Commerce Secretary Malcolm Baldrige said of President Reagan last week.

Many others disagree, citing what they say are major policy shifts by the president on taxes, budget deficits and Social Security policy.

The tax increase passed by Congress last month at the president's urging was one such shift, breaking with his commitment to reduce taxes, they argue. Before that, Reagan's February 1982 budget with its string of record-sized deficits encompassed a dramatic move away from his original goal of a balanced budget.

Earlier presidential reverses came on Social Security. In the spring of 1981, Reagan proposed a series of measures to save money for the Social Security program. After a political outcry, he dropped the proposals and set up a bipartisan presidential commission on Social Security, to report after this year's elections.

The White House clearly has decided that it is politically advantageous for Reagan to appear consistent and constant. Wall Street may have rejoiced this summer at the president's change of heart over taxes, but many Republicans--and perhaps many voters -- did not. Moreover, while Reagan pushed vigorously for a tax increase this summer, which will save $98.3 billion over three years and $214 billion over the next five years, he did so reluctantly.

"I do believe he feels he hasn't changed" course, one administration official said last week, adding that in this view the president was "just making practical adjustments" to policy to preserve the overall thrust of his program.

The key question for the future is whether Reagan will make such "practical adjustments" again and, if he does, how these will affect the economy.

Many outsiders have felt from the beginning of Reagan's presidency that his economic program would have to be modified, or at the least that he would have to choose between its goals. Both liberal and conservative economists argued that it would prove impossible to fight inflation and boost growth simultaneously.

Similarly, many said the president would be unable to cut taxes as much as he planned, boost defense spending to the extent that he wished and balance the budget by the end of his first term in office.

Both of these prophecies so far have come true.

Reagan has not made the explicit choice to stifle inflation and let the economy stagnate. But the deep recession of the last year, with falling inflation and rising unemployment, shows that so far anti-inflation policy has in fact taken precedence over job creation.

The president has had to make a more obvious choice between conflicting budgetary aims. Early on, it became clear that defense spending had a higher priority than budget balancing. In the summer of 1981, the president first overruled attempts by budget director David Stockman and some other senior officials to get a reduction in planned defense spending. Although the president still insisted publicly that the budget could be in balance by 1984, few believed him.

Reagan's resistance to raising taxes became clear in January, when he rejected the advice of all his senior advisers and decided against raising excise taxes in the budget. "I will seek no tax increses this year," Reagan declared.

But while he chose large deficits over a significant increase in taxes for the first half of this year, by midsummer the balance had shifted.

Paradoxically, one main factor behind Reagan's shift on the tax bill was that the recession proved to be worse than he expected. In normal times a tax increase comes in response to an overheated economy, not to one sinking deeper into recession.

The president finally was won over, however, by the argument that large deficits stall the economy by keeping interest rates high. Concern over the budget deficit "came to the fore because of the unexpected stubbornness of the high interest rates that were in place when we got here," Baldrige said.

Most analysts -- including those within the administration -- believe the budget problem remains huge, despite the tax bill. "This issue will be faced year in and year out," one Treasury official remarked last week.

This official believes that those arguing for further tax increases next year will be in a weaker position after this year's tax boost. The president was reluctant to back a tax increase this year and would be even more unwilling to go further in undoing his multi-year tax cut program, his greatest congressional victory of 1981, the official argued.

Others believe that having once compromised on taxes to help reduce the deficit, Reagan will do so again more easily. The sharp drop in interest rates and the stock market boom of recent weeks has strengthened the hand of those who blamed high interest rates on the big prospective deficits. Moreover, the most fervent supply-side opponents of tax increases -- other than the president -- now have left the administration.

Democrats may try to push for further increases in taxes next year. But major battles for budget savings also are likely to come over defense, some observers believe. Reagan has consistently slapped down officials who have pushed for a curb in Pentagon expansion. But his first notable legislative defeat, on the supplemental appropriations bill, came when he pushed for still more spending on defense and less on social programs than Congress originally voted.

The rebuff from the Republican Senate as well as the Democratic House could signal difficulties ahead for the presidential push to shift the focus of government spending still further from domestic to military programs.

As a recent study by the Urban Institute noted, Reagan already has achieved a tremendous shift in spending priorities.

According to the Congressional Budget Office, the share of public spending in the economy is likely to be the same by the end of Reagan's first term as it was at the beginning. But the pattern of spending will be dramatically different, with much more going to defense and for interest on the national debt, and much less going to social and other domestic programs.

Although the 1984 budget already is in preparation, none of the major issues will come up for discussion at a senior level until after the election, sources said. But already Stockman has warned that still further big spending cuts will be proposed next year.

This time Social Security is unlikely to be sacrosanct. Other domestic programs will be combed for more cuts.

Reagan has been forced to give up on his promises to balance the budget. The budget deficits projected under his program will add hugely to the size of the national debt.

But Reagan's success in shifting the focus of government spending, and tilting the balance of the tax burden a little away from business and the well-to-do, has been remarkable. By those measures, his economic program has achieved much of what he set out to do, and indeed has remained constant.

Next year's budget is likely to emphasize the present thrust of overall economic policy towards curbing inflation rather than boosting output. The president and Congress want to make further cuts in the large budget deficits now forecast by most analysts. If they succeed, then fiscal policy will be more in line with anti-inflation monetary policy, rather than being set towards expansion.

The fact that the big deficits have failed to stop the recession or to raise hopes of a buoyant recovery, as past experience would indicate, illustrates the strength of the tight, anti-inflation monetary policy administered by the Federal Reserve Board.

Significantly, the administration has not backed away from its support for the Federal Reserve's overall money policy, a shift that was widely anticipated this summer.

Despite frequent complaints that the Fed was keeping interest rates high through erratic and mismanaged policy, the White House generally has steered clear of asking for easier credit and more money growth.

The recent drop in interest rates, of course, makes it easier for the administration to support the Fed. Officials hope that with lower rates the slump will soon give way to recovery.

But the modest recovery now in the cards is still a far cry from the "healthy, vigorous growing economy," aimed at "putting America back to work," that Reagan looked forward to in his inaugural address.