The music was blaring, the hair dryers humming and the hair stylists laughing in the beauty salon as one of them, Kathia Mendez, loosened her curlers and let her black hair tumble to her shoulders. To many Americans, the vivacious young woman smiling into the gilded mirror might seem easily recognizable as a black woman.

But like many Hispanics here, Ms. Mendez views race through a decidedly different lens. In her home country, the Dominican Republic, she is known as "india," or Indian, a term often used for people of mixed race who do not have indigenous roots. If she was asked to describe herself in the United States census, she says, she would choose the racial category selected by nearly 15 million Hispanics in 2000: "some other race."

Not Black, Not White: 'Some Other Race'?

"I'm not black and I'm not white; we don't define ourselves that way," said Ms. Mendez, a 25-year-old hair stylist who has lived in the United States for nine years. "So I would choose 'some other race.' ''

But now census officials are hoping to eliminate the option from the 2010 questionnaire in an effort to encourage Hispanics to choose one or more of five standard racial categories: white, black, Asian, American Indian or Alaska native, or a category that includes natives of Hawaii and the Pacific Islands.

Over the last three decades, the number of Hispanics choosing "some other race" has surged rapidly, making it the Census Bureau's fastest growing racial category. Census officials say the proposed change, which is expected to remain under consideration until 2006, would improve the accuracy of the nation's racial data because federal agencies typically rely on data from the standard racial groups to make statistical calculations about race.

How Should Hispanic-Americans Be Identified?

The proposal to eliminate the category, which was used almost exclusively by Hispanics in the 2000 census, has stirred a furious debate among Hispanic advocacy groups, statisticians and officials over how the nation's largest minority group should be defined racially.

If approved, the shift would be the first time since 1940 that officials have eliminated a racial category from the census, Census Bureau officials say.

Critics say the change would ignore the evolving views of race emerging in communities across the country as immigration from Latin America has surged in recent decades. Nearly 40 million Hispanics - almost half of them immigrants - live in the United States and many embrace a kaleidoscope of racial identities that transcends traditional notions of black and white.

Jabao, Indio, Trigueño or Moreno?

Many Hispanics refer to themselves as jabao, indio, trigueño or moreno, depending on their skin color and birthplace, while others think that all Hispanics, regardless of color or national origin, should be viewed as a single race.

In the 2000 census, 48 percent of Hispanics described themselves as white and 2 percent as black. Six percent identified themselves as belonging to two or more of the standard racial categories. And 42 percent chose "some other race," with the vast majority writing in responses like Hispanic, Latino or geographic backgrounds like Mexican, Puerto Rican or Dominican.

Carlos Chardon, chairman of the Census Bureau's Hispanic advisory committee and an opponent of the proposed change, said census officials were ignoring America's shifting racial realities by trying to force Latinos to choose one or more of the standard categories. Advocates at the Puerto Rican Legal Defense and Education Fund and the Mexican American Legal Defense and Education Fund have also expressed concerns.

"We don't fit into the categories that the Anglos want us to fit in," Mr. Chardon said. "The census is trying to create a reality that doesn't exist."

Census officials say they will consult with the Office of Management and Budget, which governs federal statistics, Congress and advocacy groups before a final decision is made. But they say change is necessary to improve the accuracy of the data in the bureau's Modified Age/Race and Sex, or MARS, file, which many federal agencies rely on.

In the MARS file, census officials assign a race to those who select "some other race'' and include them in standard racial groups to accommodate federal agencies that do not use the ambiguous racial category. Federal agencies use estimates from the MARS files to track population and birth and mortality rates, among other things.

Census demographers look for clues to make such determinations, checking to see whether relatives are listed in standard racial categories and checking neighborhood demographics. Census officials say the process is flawed and needs changing, even though they understand that sociologists and advocacy groups want to continue tracking and studying Hispanics who choose the "some other race" category.

Racial Identity is an Emotional Issue; 'Latino' Isn't Definitive

"The race question and race in the United States is a very emotional issue and people who are interested in it feel very strongly about it," said Preston Jay Waite, associate director for the decennial census.

"But if somebody writes down that their race is Latino, that doesn't give us any information about which of the race categories they're in," Mr. Waite said. "We're making up the race for 15 million people. We would prefer not to do it. It doesn't seem wise to me that we would put at risk the racial statistics of the nation in order to answer an interesting sociological question."

Some statisticians question the need for change, however, and warn that eliminating the category would create new problems in census files used for political redistricting and enforcement of equal opportunity laws.

Removing the option would increase the number of Hispanics who would include themselves in traditional racial groups and would probably increase the number of those who would identify themselves as white, census officials say. But it would also increase the number of Latinos who would simply refuse to respond to the race question, according to recent tests conducted by the Census Bureau.

Officials have to guess the race of individuals who do not respond, and an increase in those numbers could lead to inaccuracies in data files used to monitor voting rights and civil rights enforcement, said Roderick J. Harrison, a demographer at the Joint Center for Political and Economic Studies, a research group in Washington that studies issues of concern to blacks.

He said mistakes in categorizing the race of Hispanics who do not respond to the race question could result in inaccurate tallies of blacks, whites or other racial groups in a given community, a major worry for those concerned about redistricting and civil rights issues.

"That's a major concern," said Mr. Harrison, who headed the racial statistics unit at the Census Bureau from 1990 to 1997. "It's not clear what the positive tradeoff is from dropping 'some other race.' I don't know that any federal agency has complained about the category or the quality of the MARS file.''

In a meeting of members of a steering committee that disseminates census data to minority groups, a discussion earlier this year between Mr. Waite and Mr. Harrison on this subject grew so heated that Mr. Harrison was asked to resign from the committee. Hispanic and Native American advocacy groups expressed concern about the resignation, and Representative William Lacy Clay, Democrat of Missouri, said he believed Mr. Harrison was forced out for challenging the Census Bureau's conclusions, a charge that Mr. Waite denies.

The dispute highlights the difficulties the Census Bureau has encountered over the decades as it has struggled to find a racial home for Hispanics living in this country.

From 1930-1940, 'Mexican' Was an Option

In 1930, the census introduced a racial category called Mexican, which was intended to capture the growing number of Hispanics in Southwestern states. But it was dropped in 1940, and by 1960 census officials were instructing its interviewers to record "Puerto Ricans, Mexicans or other person of Latin American descent as white unless they were definitely of Negro, Indian or other nonwhite race."

The "other race" category, on the other hand, was made up of mixed-race people who claimed some combination of white, black and Native American descent and some people of Asian heritage when it was first included in the census in 1950. By 1980, the category was largely Hispanic, reflecting, in part, the increased immigration from Latin America.

At Arelis Beauty Salon, Ms. Mendez and her colleagues marveled at the differences between the Dominican and American racial palettes as they styled hair and waxed eyebrows and debated whether the census reflected their racial identities.

Zunilda Diaz, 48, said she would describe herself as white even though her mother is a dark-skinned woman who would be considered black in the United States. Nelly de la Rosa, who is 33 and has chocolate brown skin, said she would choose "some other race."

Without that option, she said, she would be hard pressed to pick a racial category.

"We have so much mixture," said Ms. de la Rosa, who said she is described as morena or india at home. "These other census categories just don't reflect who we are."