Census of Population and Housing, 1990: Modified Age/Race, Sex and Hispanic Origin (MARS) File (STF-S-2B)

<p>The MARS file contains modified race and age data based on the 1990 Census. Both race and age are tabulated by sex and Hispanic origin for several layers of geography. The race data were modified to make reporting categories comparable to those used by state and local agencies. The 1990 Census included 9,804,847 persons who checked the "other race" category and were therefore not included in one of the 15 racial categories listed on the Census form. "Other race" is usually not an acceptable reporting category for state and local agencies. Therefore, the Census Bureau assigned each "other race" person to the specified race reported by another person geographically close with an identical response to the Hispanic-origin question. Hispanic origin was taken into account because over 95 percent of the "other race" persons were of Hispanic origin. (Hispanic-origin persons may be of any race.) The assignment of race to Hispanic-origin persons did not affect the Hispanic-origin category that they checked (i.e, Mexican, Puerto Rican, Cuban, etc.). Age data were modified because respondents tended to report age as of the date they completed the 1990 questionnaire, instead of age as of the April 1, 1990 Census date. In addition, there may have been a tendency for respondents to round up their age if they were close to having a birthday. Age data for individuals in households were modified by adjusting the reported birth-year data by race and sex for each of the 1990 Census's 449 district offices to correspond with the national level quarterly distribution of births available from the National Center for Health Statistics. The data for persons in group quarters were adjusted similarly, but on a state basis. The age adjustment affects approximately 100 million people. In this file their adjusted age is one year different from that reported in the 1990 Census. STF-S-2B only contains data for 12 states, their counties, and Minor Civil Divisions (MCDs). (Source: ICPSR, retrieved 06/15/2011)</p>

MARS数据集（MARS）包含基于1990年人口普查修订后的种族与年龄统计数据。种族与年龄数据均按性别、西班牙裔血统及多层级地理区划进行制表统计。种族数据经过修订，以确保其填报分类与州及地方机构所采用的分类标准保持一致。

1990年人口普查共有9804847名受访者勾选了“其他种族”分类，因此未被纳入普查表格所列的15个标准种族分类中。“其他种族”通常不被州及地方机构视为合规的填报分类。为此，美国人口普查局将每一位勾选“其他种族”的受访者，按照地理邻近且对西班牙裔血统问题作答一致的其他受访者所填报的种族进行归类。之所以考虑西班牙裔血统因素，是因为超过95%的“其他种族”受访者均为西班牙裔血统（西班牙裔血统人群可属于任何种族）。对西班牙裔血统人群的种族归类，不会改变其原本勾选的西班牙裔血统分类（如墨西哥裔、波多黎各裔、古巴裔等）。

年龄数据同样经过修订，原因在于受访者往往填报的是完成1990年普查问卷当日的年龄，而非普查基准日（1990年4月1日）的实际年龄。此外，部分受访者在临近生日时可能会倾向于上报略高的年龄。针对家庭户内个体的年龄数据，普查局按1990年人口普查的449个地区办事处为单位，基于种族与性别对上报的出生年份数据进行调整，使其与美国国家卫生统计中心（National Center for Health Statistics）公布的全国季度出生人口分布数据保持一致。集体住宿场所内人员的年龄数据则采用类似方式调整，但调整基准为州级层面。

此次年龄调整共涉及约1亿人口，在本数据集中，这批人群的调整后年龄与1990年人口普查上报的年龄相差1岁。

STF-S-2B数据集仅包含12个州及其下辖县、基层民政分区（Minor Civil Divisions, MCD）的相关统计数据。