question: Which job categories did the study consider and for how long? answer: The study considered descrimination in at least one job category from 1990 to 1999 paragraph: Women and minorities appear to be benefiting from greater employment opportunities in the United States, but discrimination remains a significant problem, according to a study to be released today by two professors at the Rutgers School of Law in Newark. The study, which extrapolated from federal data on about 200,000 large and midsize employers, concludes that about two million workers were affected by intentional discrimination in 1999. Roughly a third of the employers studied appeared to have discriminated against women or minorities in at least one job category, the authors said The study was based on information collected from employers by the Equal Employment Opportunity Commission from 1990 through 1999 on so-called EEO-1 forms. The husband-and-wife team of Alfred W. and Ruth G. Blumrosen then looked at how many women or minority workers a company employed in different job categories compared with how many were employed at other companies in the same industry in the same geographic area. They described a company as an intentional discriminator if its employment of women or minorities was at least two standard deviations from the average. Legally, companies are presumed to discriminate if their employment numbers are far below the norm. About 22,000 employers were identified as "hard core" discriminators. These companies employed below-average numbers of women and minorities for 10 years and their hiring of women or minorities was so far below the averages that there was only one chance in a hundred that the discrimination occurred randomly. The study also found rising employment for women and minorities, suggesting significant progress in the workplace. The names of the companies are confidential and were not known to the researchers. The professors expect to make their study available through a Web site, www.eeo1.com. The Blumrosens, who were instrumental in setting up the E.E.O.C. in 1965, also say the government should make more active use of their data. The commission said it did not comment on draft reports. 