The Reagan administration was much denounced as the poverty rate went up in its early years in office. Now the Census Bureau has announced that last year the figures turned. Having steadily risen for five years beginning midway in the Carter term, the rate declined, from 15.3 to 14.4 percent.

There is a tendency among those who emphasized the earlier increases to minimize the current decline. Not fair. If up was bad -- and it was -- then down must be as good. The administration has defended itself on the fairness issue -- the charge that it cut spending programs for the poor to finance tax cuts for the rich -- by saying the poor would end up better off under its program, because high inflation would be replaced by steady economic growth. The president's spokesmen thus found vindication in the new figures. Within the limits of this kind of scorekeeping, they are entitled.

Still, their optimism is narrowly focused. It magnifies the good news -- the accomplishments of the last year, "sharpest decline in 16 years" in poverty, median income up all around -- while ignoring the bad, the level of poverty that remains. In these absolute terms the new report leaves scant room for rejoicing; parts of it are downright frightening. The economy is now well into its recovery from the last, deep recession. Yet the poverty rate, while down slightly from its level in those recession years, is otherwise the highest it has been since 1966. In the five years from 1979 through 1983 poverty increased by about a third. High inflation, then high unemployment, budget cuts and continuing population shifts all took a toll. The recovery simply can not overcome all these. At least for a while, large parts of the population have lost important ground.

The elderly, who used to be so vulnerable, are not among them. Thanks largely to indexed Social Security payments, their poverty rate -- over 30 percent 25 years ago -- declined last year to 12.4 percent, the lowest ever (and counting in-kind benefits, it fell even more). That is one of the great social accomplishments of our time. It is the young who now are disproportionately poor -- children, particularly if they are black or Hispanic. The poverty rate for all children under 18 was 21 percent, for Hispanic children 38.7 percent, for black children 46.2. Of the 33.7 million poor people last year, 12.9 million -- 35 percent -- were children.

In part this can be attributed to factors over which government has little control. The family has become a weaker economic unit; over 20 percent of all children, and 50 percent of all black children, now have only one parent in the home. Many Hispanics are recent arrivals, just starting up the economic ladder. There may also have been a shift in the economy toward lower-paying jobs.

In one sense this is a comforting view of the problem, precisely because it suggests that little can be done; among the nonpoor, it reduces responsibility. But policy has bitten as well. The minimum wage has not been raised since 1981. Benefits under Aid to Families with Dependent Children, which are set by the states, have been allowed to fall 35 percent behind inflation in the last 15 years. In 1979, the staff of a House Ways and Means subcommittee has estimated, government welfare programs lifted out of poverty 33.1 percent of families headed by women who would have been below the poverty level had those programs not existed. By last year this measure of public beneficence had fallen to 19.7 percent.

The poorest two-fifths of all families received 15.7 percent of all income last year, the lowest share on record. The richest fifth received 42.9 percent, the highest share since 1948. The redistributive mechanisms that are at the heart of the government have been weakened in recent years. The poverty figures are an improvement over the year before. They are also shameful -- and the recovering economy on its own cannot turn them around. The administration and Congress must deal with them. The society cannot be allowed to split this way.