The federal Department of Education would categorize Michelle Lopez-Mullins — a university student who is of Peruvian, Chinese, Irish, Shawnee and Cherokee descent — as “Hispanic.” But the National Center for Health Statistics, the government agency that tracks data on births and deaths, would pronounce her “Asian.” And what does Lopez-Mullins’ birth certificate from the state of Maryland say? It doesn’t mention her race.

Lopez-Mullins, 20, usually marks “other” on surveys these days, but when she filled out a census form last year, she chose Asian, Hispanic, Native American and white.

The chameleon-like quality of Lopez-Mullins’ racial and ethnic identification might seem trivial except that statistics on ethnicity and race are used for many important purposes. These include assessing disparities in health, education, employment and housing, enforcing civil rights protections, and deciding who might qualify for special consideration as members of underrepresented minority groups.

But when it comes to keeping racial statistics, the nation is in transition, moving, often without uniformity, from the old “mark one box” limit to allowing citizens to check as many boxes as their backgrounds demand. Changes in how Americans are counted by race and ethnicity are meant to improve the precision with which the nation’s growing diversity is gauged: the number of mixed-race Americans, for example, is rising rapidly, largely because of increases in immigration and intermarriage in the past two decades. (One in seven new marriages is now interracial or interethnic.)

In the process, however, a measurement problem has emerged. Despite the federal government’s setting standards more than a decade ago, data on race and ethnicity are being collected and aggregated in an assortment of ways. The lack of uniformity is making comparison and analysis extremely difficult across fields and across time.

Under Department of Education requirementsthat take effect this year, for instance, any student like Lopez-Mullins who acknowledges even partial Hispanic ethnicity will, regardless of race, be reported to federal officials only as Hispanic. And students of non-Hispanic mixed parentage who choose more than one race will be placed in a “two or more races” category, a catchall that detractors describe as inadequately detailed. A child of black and American Indian parents, for example, would be in the same category as, say, a child of white and Asian parents.

The new standards for kindergarten through 12th grades and higher education will probably increase the nationwide student population of Hispanics and could erase some “black” students who will now be counted as Hispanic or as multiracial (in the “two or more races category”). And reclassifying large numbers of white Hispanic students as simply Hispanic has the potential to mask the difference between minority and white students’ test scores, grades and graduation rates — the so-called achievement gap, a target of federal reform efforts that has plagued schools for decades.

“They’re all lumped together — blacks, Asians and Latinos — and they all look the same from the data perspective,” said Daniel Losen, a policy expert for the Civil Rights Project at the University of California, Los Angeles, referring to the Department of Education aggregation. “But the reality is much different. There are different kinds of discrimination experienced by these subgroups.

”It’s a big problem for researchers,“ Losen continued, ”because it throws a monkey wrench in our efforts at accountability, student tracking and the study of trends.

Education officials say the changes will more accurately reflect how Americans see themselves. The standards were also devised to save schools time and money. If schools were to report on every possible racial and ethnic combination to the federal authorities, there would be dozens of possibilities. It is simply easier to call students ”two or more races.“

”Ultimately, the department’s final requirements aim to strike the balance,“ said Russlynn Ali, the department’s assistant secretary for civil rights, ”between minimizing the burden for local education agencies while also ensuring the availability of high-quality racial and ethnic data.“

But critics, including elected officials and the Citizens’ Commission on Civil Rights, a Washington group that monitors federal policy and practices, have called the move disturbing and want more transparency. While the policy was still in developmental stages, the commission urged the Department of Education to ”evaluate alternative approaches, including those adopted by the U.S. Census“ to track students’ race.

  In 2006, 62 members of Congress signed a letter to the education secretary at the time, Margaret Spellings, expressing ”utmost concern“ about the changes. And research by the Harvard Civil Rights Project in 2006 showed that the new method of race reporting would have a significant reduction in the black student population nationally, producing data that it called ”questionable and often meaningless.“

That could affect responsibilities held by the Department of Education in areas including civil rights enforcement, program monitoring and the identification and placement of students in special education. The numbers also affect areas like research and statistical analysis, and school and teacher accountability when it comes to student achievement and academic progress.”We believe that these changes are not supported by good research,“ the Harvard report stated.

In the late 1990s, the Census Bureau abandoned the idea of a catchall ”multiracial“ classification in favor of letting people check more than one box, in part because many Americans did not understand what multiracial meant. And a federal task force had concluded that creating a multiracial category would ”add to racial tensions and further fragmentation“ of the population.

The NAACP had vowed ”vigorous resistance“ to the notion of a multiracial catchall, concerned that such an option would diminish minority numbers, particularly blacks, in government counts.

But Project RACE, for Reclassify All Children Equally, one of the largest and most vocal multiracial advocacy groups, and its president, Susan Graham, a white mother of biracial children, were among those who had pushed equally hard for a multiracial classification.

”It is simply ridiculous that multiracial children should have to have the sanction and approval of other minority groups in order to have their own identity,“ Graham testified before Congress in 1997.

The Census Bureau’s solution may have added layers of complexity for demographers — creating 63 categories of possible racial combinations — but it laid to rest fears from civil rights advocates that adding a multiracial category would diminish the number of blacks, Asians or American Indians in official government counts, since multiracial people are counted in the ranks of all of the races they check. (This does not distort the total U.S. population because that number is based on how many people answer the census questionnaire, not on adding the totals from each racial column.)

Even the Census Bureau acknowledges that accurately counting the multiracial population is a challenge and says it continues to explore ways to do it better, said Nicholas Jones, chief of the racial statistics branch. Some people of mixed race were fickle about their racial identifications in early tests of the new, more expansive methods, changing their answers from interview to interview.

Moreover, because the census in 2000 began allowing respondents to mark as many races as they wanted, today’s numbers are not directly comparable with those before 2000.

The National Center for Health Statistics collects vital statistics from the states to document the health of the population. When it comes to collecting birth certificate information, though, the center encounters a problem: 38 states and the District of Columbia report race data in the new and more expansive manner that allows for the recording of more than one race. But a dozen states do not, because they still use old data systems and outdated forms. As a result, the center cannot produce consistent national data for what it calls ”medical and health purposes only.“

To get around that problem, the center reclassifies mixed-race births using a complex algorithm. For example, a birth to a parent who marked white, Asian and Native American would be declared just one of those races, depending on a number of variables in a probability model, like sex, age of the mother and place of birth. (Birth data is reported, in most cases, by the race of the mother.)

States were supposed to begin moving to the new way of collecting data in 2003, but a lack of resources has proved a hurdle for many and forced the center for health statistics to come up with this solution, which officials call temporary.

”There are over 4 million births every year, so we can’t possibly get back to the mother and see which race she would prefer,“ said Stephanie Ventura, chief of the reproductive statistics branch at the center. ”We don’t do that on birth or death certificates.“

Speaking of the complexities of keeping track of people by race now that the multiracial population is growing, Jeffrey S. Passel, a senior demographer at the Pew Hispanic Center, said, ”The issue is multiplied manifold if you start thinking about HR departments and private firms.“

The Equal Employment Opportunity Commission mandates that most companies provide an annual count of their workers by race, ethnicity and gender. (The EEOC strongly suggests that companies ask workers how they identity themselves, as opposed to making assumptions based on appearance.) In 2007, the EEOC added a ”two or more races“ category.

Today, federal education officials defend their changes as an improvement over the more limited choices of the past, when students were identified by only one race and Hispanics were often undercounted. They also say they are merely trying to abide by orders from the Office of Management and Budget — which sets standards on how federal agencies keep statistics — that all agencies try to collect data in a two-part question: the first focused on Hispanic ethnicity and the second on race, allowing the reporting of more than one.

”The department strongly believes that the new requirements will help educators and others better serve students who identify with more than one race and Hispanic/Latino students, which is the fastest growing population in our schools today,“ said Ali, the assistant education secretary.

Further, she said, schools are required to retain the original, more detailed answers to racial survey questions that they collect but do not report to the federal authorities — in case discrimination complaints arise, for instance.

”If our goal is to gather better information,“ said Louie Gong, a former president of Mavin, a mixed-race advocacy group based in Seattle, ”then you’d think we wouldn’t begin by arbitrarily reallocating people to categories they didn’t pick.“

© 2011 The New York Times Company