More poor Americans slip below federal poverty line

The US Census Bureau reports that 32 million Americans lived below the $9,287 poverty line (for a family of four) last year, or 14 percent of the population.

This is an increase over the 13.2 percent of the year before, and it is the third year in a row that poverty has increased. It reflects America's 9.5 percent unemployment rate in the current recession. And it is the basis of the economic debate churning in Washington, a debate that now seems to be heading toward some kind of a turning point.

After half a year, there is a widespread feeling here that ''supply-side economics'' - the theory that cutting taxes would boost federal income - isn't working, and Congress is going back to a more conventional approach. With its eye on current statistics, Congress notes that inflation is apparently slowing down, that the Federal Reserve System is moderating its tight-money policy, and that the previous drop in overall national production has leveled off in the latest quarter. What all this means is that the average American family hasn't been able to keep up with rising prices so its standard of living has gone down.

The Labor Department reports that at some time in 1981 one of every five American workers was unemployed. This total is 23.4 million or 2 million more than the figure reached in 1980.

The Census Bureau, meanwhile, estimates that the ''median family income'' was median as below it.) The income was numerically above the year before (1980) when it was $21,023. But goods cost more; inflation represented a cut in real purchasing power of about 3.5 percent - a drop for the second consecutive year.

The ''poverty line'' is an arbitrary figure set by the Census Bureau for a family of four. The present level is the highest since 1968, and the 1.4 percent increase between 1979 and 1980 was the biggest one-year increase since 1959. Poverty in America is still mostly white, but in racial percentages blacks are high - 30 percent, though they make up only 12 percent of the population. Children make up two-fifths of the poor, or 11.4 million. Critics charge that the Census Bureau exaggerates poverty by failing to count food stamps and other noncash benefits like medicare.

The poverty line is raised each year to reflect price increases. The Census Bureau says that the recession, which began in the middle of 1981, combined with the rise in consumer prices and unemployment to thrust many families back into poverty. Numerically the census figure rose from 29,640,000 to 31,822,000.

The median American family has been buffeted in the past 10 years. Real income increased by less than 1 percent. For the white family it increased a full 1 percent but for the black family it dropped 5 percent. In a recession the lower income workers are often the first to be laid off.

A statistician at the Census Bureau explained that between 1960 and 1970 there was a slight reduction of inequality between the rich and the poor, according to its way of measuring the difference. Between 1979 and 1980 ''there was a return to the 1960 level of inequality.''