CRIME pays financially for many young black males - at least in the short term.That's one reason so many of them are engaged in criminal activities - car theft, drug peddling, and so on, says Richard Freeman, a Harvard University economist. Those with poor education, particularly, earn more in crime than in legitimate jobs. Newspapers, television, and radio carry frequent stories about crime in poor inner-city neighborhoods. "Unlike some sensational reporting, the stories reflect reality," states Mr. Freeman. In a paper written for the National Bureau of Economic Research, Freeman finds that one-fifth of black men between 16 and 34 years old (not just those in the ghettoes) and upward of three-fourths of black high-school dropouts aged 25 to 34 had criminal records in the 1980s. "These magnitudes are astounding," notes Freeman in a telephone interview. He figures the proportion of disadvantaged young black men with criminal records grew so large in the 1980s that "crime became a major determinant of their economic life rather than deviant behavior on the margin." Young black offenders and ex-offenders tend to be outside the mainstream of society, an "underclass," he adds. This development "suggests a major change in the nature of poverty and youth unemployment from that of the previous decades." It is not just a topic for criminologists or ethnographers of deviance, but one for economists, sociologists, and policy analysts, he maintains. In his paper, Freeman doesn't deal directly with the moral issues involved in this extremely high crime rate among black youths. His paper merely presents evidence that the decision to engage in crime has at least a short-run economic rationale in terms of high hourly pay. In the longer run, many of these black youths go to jail. And their criminal records make it more difficult for them to obtain legitimate jobs. "Economists are not the types to make moral judgments," he says over the phone. He does mention that many black youths are not given much moral training, but that those with a religious background are often saved from criminal activities. Male youths of all races are tempted by crime. In 1989, 2 percent of all 16- to 34-year-old men were incarcerated and nearly 7 percent were "under supervision of the criminal justice system," that is, under parole or probation. The numbers are a magnitude greater for blacks - 7 percent and 20 percent. This difference isn't merely the result of a tendency of courts to be tougher on blacks, Freeman's surveys and statistics indicate. One survey of youths in the lowest income neighborhoods of Boston in 1989, during the period of the "Massachusetts miracle" when jobs were plentiful, found that only 55 percent of out-of-school youths were working. This shows that a tight job market was not sufficient to resolve the youth crime problem, says Freeman. Many chose crime as a means of support. Youths who committed crimes were 19 percent less likely to be working than others. The more crimes committed or the greater the income from crime, the smaller is the chance of having a legitimate job. Analyzing admittedly shaky numbers on the income of crime, Freeman finds that men with limited skills earn hourly rates of pay that are on the order of twice those from legitimate work possibly much greater." After a decade of declining incomes for those with less education, 63 percent of disadvantaged youths in poverty areas in 1989 said they could make more "on the street." The other side of the crime coin is the prospect of prison, injury, or being killed. Drug dealers spend one-third of their careers in jail. Youths are aware of the risks, but take them. What can be done? Freeman sees the need for higher-paying opportunities for these disadvantaged youths. "Our society doesn't seem to have anything legitimate for them to do," he says. He likes the idea of an expansion of income-tax credits that would boost the real income of workers receiving low pay. He recommends more efforts at rehabilitation and education in jails. Crime should be penalized with more certainty. Most of all, he would like dramatic changes in the "whole structure" of poor black communi ties so that there is less peer pressure in favor of crime. "I don't know how you do that," he concedes.