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Method simplifies race data

To compare this census with the last, 63 race categories are telescoped down to five.


© St. Petersburg Times, published March 28, 2001

To compare this census with the last, 63 race categories are telescoped down to five.

In order to compare 1990 to 2000 Census race numbers, the St. Petersburg Times used a formula to fold the 63 race categories from this census into the five from the last.

The method, created by Arizona State University professor Steven Doig, essentially counts the number of checks a person filling out the census makes and then divides people into the 1990 categories. The method is a combination of two methods created by the federal Office of Management and Budget.

Under the method, called a race bridge, if 60 people marked that they were a combination of black, Asian and American Indian, they would be assigned back to 1990 categories as 20 blacks, 20 Asians and 20 American Indians.

However, if someone responded that they were part white, the bridge method would assign them to their other racial category. For instance, if 20 people marked that they were white and black, they would be counted as 20 blacks.

That estimation method is used because under federal civil rights guidelines, a person claiming part white and part another race would be counted as the other race.

Nationally, 2.4 percent of the population, or just more than 6-million people, marked that they were of mixed race.

Another method the Times used to measure diversity is the USA Today Diversity Index. The Diversity Index measures the chance that taking two people at random from a place will result in two people of different race. Unlike race data, the diversity index for 2000 is directly comparable to 1990.

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