A primary research on the population influence on ecological environment in the mountain area of the South An Hui Province]

The 16 counties in the mountain region of South Anhui Province have a land mass of 29,176 sq. km and a 1983 population of 491,720,000, a majority of whom are farmers. Forests, tea and grains are the villages' major sources of income. 80% of the area is hilly; the climate is temperate and rainfall is adequate. In recent years, a rapid population increase and inattention to proper use of natural resources have eroded the environment. Since 1949 the population of this area increased 70%, putting tremendous pressure on the land and fuel. The demand for housing, factories, transportation and communication to accomodate the population increase constantly decreases the availability of farmland. Arable land decreased by about 3,000,000 sq. acres between 1949 and 1983. Because the average individual acreage is small, production is low, leading to frequent grain shortages. Forests are then destroyed to make farmland, but in the process, the flora and fauna are disturbed while production remains low and uneven. In addition, firewood, the main source of fuel, will not be replenished rapidly enough to meet the needs of the growing population. The quality of this mountain population also influences ecology. Almost 80% of the people are semi-literate, traditional in their attitudes and customs, and unreceptive to new ideas. Family planning has not been successful here, nor is there a deep understanding of the consequences of deforestation. It is necessary, then, to control this area's population growth, improve the population's quality, raise its environmental consciousness, and utilize its resources effectively.     

Fertility of U.S. farm women during the electrification era, 1930–1950

The research reported here examines the fertility of U.S. farm women during the period in which rural America became electrified. It suggests that electrification was relatedly indirectly to fertility through the impact it had on farm and home production modes, and also through its facilitation of more general socioeconomic change. The model is tested using Census and Agricultural Census data for 473 rural farm counties at three points in time — 1930, 1940, and 1950. Overall, the results of multivariate analyses generally support the conceptual model. The effects of farm production/technology factors, electrification, and sociodemographic characteristics are evaluated using OLS. The effects of electrification net of the other variables are significant when subsamples of Southern and non-Southern counties are examined separately, with electrification related to lower fertility in Southern counties and higher fertility in non-Southern counties. The findings emphasize the importance of considering potential demographic impacts when introducting rural development projects in developing countries.     

Using administrative data to estimate population displacement and resettlement following a catastrophic U.S. disaster

After a large scale evacuation, authorities need to know the new and frequently changing population distributions in order to meet needs for housing, schools, health care, and other services. This paper reviews literature from the fields of demography and other disciplines to identify available administrative data sets that can form the basis of sound, relevant, and timely county-level population estimates following a catastrophic U.S. event. The most appropriate data to estimate population in damaged counties will be disaster-specific data such as housing damage estimates and FEMA applicant counts initially, and later electric accounts and USPS active residences. In heavily damaged counties, data on electric accounts and USPS active residences may not be consistently collected for many months, during which time sample surveys may be needed. For counties that receive an influx of population, school enrollment data provide the most appropriate basis for population estimates. Population estimates for large, heavily damaged counties are highly uncertain. Sensitivity analysis when using estimates for planning in these areas is recommended. The Census Bureau can build on this research by codifying recommendations to local authorities for developing frequent post-disaster population estimates.     

The American Community Survey in counties with “seasonal” populations

The U.S. Census Bureau designed the American Community Survey (ACS) to provide annual estimates of social and economic characteristics for states, counties, municipalities, census tracts, and block groups. Because of its April 1 reference date, in northern nonmetropolitan counties with substantial seasonal population fluctuations the decennial census provides a statistical representation of the demographic and social characteristics of the population at a time when the population is close to its annual minimum. The year-round monthly ACS sample survey has the potential to provide local communities with an unprecedented understanding of the average population characteristics over the course of a year. In the future, the ACS even has the potential for providing social and economic characteristics of the population by season. This paper examines four ACS pilot data collection counties, Oneida and Vilas Counties in northern Wisconsin, and Lake and Flathead Counties in northwest Montana. We hypothesize that the ACS will reflect a resident population over the course of the year that is different from the traditional April 1 decennial census population. While the ACS holds much promise, our research uncovered some sampling problems that are not yet fully resolved. In addition, our analysis was not able to examine ACS estimates for minor civil divisions (MCDs), which are functioning governmental units in many states. The fact that these MCDs often have very small populations, together with the fact that estimated standard errors at the much larger census tract level in these counties are disconcertingly large, raises (currently unanswerable) questions concerning the eventual statistical quality of ACS estimates for small MCDs. Consequently, the adequacy of the ACS as a replacement for the census long form may depend on the ability of the Census Bureau to effectively address the concerns presented in this analysis.     

Two hundred years and counting: the 1990 census

On April 1, 1990, the US will take a national census, marking 200 years of census taking in America. A national census has been taken every 10 years in the US since 1790. Mandated by the US Constitution, the decennial census is the basis for reapportionment of the House of Representatives. California, Texas, and Florida are expected to gain the most Congressional seats following the 1990 Census, reflecting above-average population growth in these states. The census also provides important information about the characteristics of the American people, and a growing number of federal, state and local government programs, private corporations, and community agencies use census data. Each census provides a portrait of America, and over the decades these portraits have revealed much about how our country has changed as we have grown from a young agrarian nation of about 4 million people clustered along the Eastern seaboard to a complex post-industrial society of nearly 250 million spread across the continent and beyond. Techniques for taking the census have steadily improved over the past 2 centuries. The 1990 Census will rely heavily on computerization in all its aspects, including field operations, processing, geography, data tabulations, and products. It is likely to be the most accurate census in our history. The 1990 Census is already the subject of a lawsuit, however, charging that minority groups will be counted less completely than the white population. A series of similar lawsuits followed the 1980 Census, but all were unsuccessful. This Bulletin discusses the Census Bureau's plans for taking the 1990 Census, looks back on 200 years of census taking in America, and details such key aspects of the 1990 Census as the questionnaire, census geography and data dissemination plans, census undercount and the homeless.     

An Application of Bayesian Methods to Small Area Poverty Rate Estimates

Efforts to estimate various sociodemographic variables in small geographic areas are proving difficult with the replacement of the Census long-form with the American Community Survey (ACS). Researchers interested in subnational demographic processes have previously relied on Census 2000 long-form data products in order to answer research questions. ACS data products promise to begin providing up-to-date profiles of the nation’s population and economy; however, unit- and item-level nonresponse in the ACS have left researchers with gaps in subnational coverage resulting in unstable and unreliable estimates for basic demographic measures. Borrowing information from neighboring areas and across time with a spatiotemporal smoothing process based on Bayesian statistical methods, it is possible to generate more stable and accurate estimates of rates for geographic areas not represented in the ACS. This research evaluates this spatiotemporal smoothing process in its ability to derive estimates of poverty rates at the county level for the contiguous United States. These estimates are then compared to more traditional estimates produced by the US Census Bureau, and comparisons between the two methods of estimation are carried out to evaluate the practical application of this smoothing method. Our findings suggest that by using available data from the ACS only, we are able to recreate temporal and spatial patterns of poverty in US counties even in years where data are sparse. Results show that the Bayesian methodology strongly agrees with the estimates produced by the SAIPE program, even in years with little data. This methodology can be expanded to other demographic and socioeconomic data with ease.     

Population Trends in Metropolitan and Nonmetropolitan America: Selective Deconcentration and the Rural Rebound

This study uses revised annual population estimates that incorporate adjustments from the 2000 Census to backcast demographic change for U.S. counties during the 1990s. These data are supplemented with new post-censal population estimates for 2001–2003. We use these data to examine demographic trends in the late 1990s and first years of the new century. Our findings are consistent with a model suggesting that a selective deconcentration of the U.S. population is underway. Our findings also confirm the occurrence of the rural rebound in the first half of the 1990s and a waning of this rebound in the late 1990s. Post-censal data also suggest a modest upturn in nonmetropolitan population growth rates in 2001–2003.     

中国人口空间分布形态模拟与预测--基于“五普”和“六普”的分县尺度人口密度研究

人口空间分布不平衡是一个普遍现象,但其“是否有分布和统计规律”的研究议题非常鲜见。通过中国第五次和第六次人口普查的分县尺度数据模拟出中国分县尺度人口密度的概率分布函数,并进行概率分布预测,分析了未来中国人口分布统计特征。主要结论有：模拟显示,中国分县尺度人口密度符合对数正态分布形态;以2000年分县尺度数据的前向（未来）预测检验和2010年数据的后向（过去）预测检验发现,“人均产出”和“地均产出”两个条件能很好地模拟未来人口密度的分布规律;以2010年分县尺度为基础预测了2020－2100年的中国人口密度概率分布特征和趋势,结果显示中国人口分布极化特征将持续加大,例如2050年,无人区（小于1人／平方公里）的县域比例将从当前的1.02％（29个）增加到4.49％（128个）,超高密集区（大于30000人／平方公里）的区县比例将从0.11％（3个）增加到3.93％（112个）。     

At the margins: agriculture,subsidies and the shifting fate of North America’s native grassland

We examined patterns of shifting cropland cultivation in the US Great Plains from the dust bowl to the beginning of the twenty-first century, by comparing land-cover data from 400 sample sites across the region from the 1930s, 1950s, 1970s, 1990s and 2000s. The small area land-cover data were nested within 50 target counties across the region. To understand the use of marginal land for cultivation since the Great Depression, we argue, requires consideration of the long term dynamics of demography, technology and policy. We draw on these historical dynamics, and their interactions with programs aimed at reducing environmental impacts of agriculture, to tell the story of how and when marginal lands have been brought into use. In a multilevel panel design, macro- and micro-level covariates were used to predict levels of encroachment on marginal soils. We conclude that land retirement programs (like the Conservation Reserve Program) have had a generally stabilizing effect on the micro-level patterns of land use in recent decades, but that increased levels of encroachment on marginal soils and native grassland remain a problem in areas with higher or increasing population densities.     

The human ecology of tornadoes

This paper offers an empirical test of the impact of human ecological patterns and other known correlates on tornado occurrence. It uses the National Severe Storms Forecast Center’s information on tornadoes from 1950 through 1990 and employs ecological data from the U.S. Bureau of the Census and the Environmental Protection Agency. The results show that metropolitan and other urban counties have higher odds of tornado occurrence than rural counties, and that the probability of occurrence of tornadoes increases with increases in the number of previous tornadoes. The paper assesses the meaning of this finding for demographers, atmospheric scientists, engineers, and disaster managers.     

Identifying Associations Between State Medicaid Expansion Decisions and Spatial Disparities in County Insurance Rate Changes Under the Affordable Care Act

By the end of 2014, twenty-four states rejected Medicaid expansion, providing a unique opportunity to examine changes in insurance coverage rates after the implementation of the Affordable Care Act within and between states that did versus did not expand Medicaid. Using multilevel regression analyses of county-level non-elderly adult small area health insurance estimates (N = 3135) from the US Census Bureau, several important findings emerge. Compared to counties located in states that did not expand Medicaid, counties located in states that did expand experienced significantly larger increases in adult health insurance coverage rates between 2013 and 2014, net of the county baseline insurance coverage rate, socioeconomic and demographic composition, and labor market characteristics. In states that did not expand Medicaid, counties with larger shares of vulnerable residents (i.e., poor adults and low education) experienced lagging improvements in health insurance coverage. However, counties in states that expanded Medicaid were protected from several of these exacerbated disparities, and in some cases, experienced larger insurance coverage improvements than counties with less disadvantaged populations. These findings suggest that although insurance coverage increased in nearly all counties between 2013 and 2014, increases would have been larger and disparities would have been further alleviated if more states with highly concentrated vulnerable populations had expanded Medicaid.     

The socioeconomic dimensions of brownfield cleanup in the Detroit region

Although the goal of brownfield development is to clean up and redevelop abandoned or underutilized properties in distressed urban neighborhoods, the racial and socioeconomic disparities of brownfield cleanups have not been adequately examined. This study combines the locations of brownfields with 1990 and 2000 US Census data in the Detroit region. Results reveal that brownfields located near socioeconomically disadvantaged neighborhoods tend to be cleaned up first. Brownfields located far from major roads also tend to receive priority. However, results also suggest that the amount of land devoted to industrial and/or commercial uses adjacent to brownfield sites is not significantly associated with the probability of brownfield sites being cleaned up. These findings indicate that the initial step of brownfield development—cleaning up environmentally contaminated properties—is heading in the right direction.     

Population Aging and Endowment Insurance System Innovation

This paper, starting from examining the current situation for the social insurance service system, analyses the problems of the system and provides three reform suggestions. First, staffing levels of social insurance should bring about a dynamical ratio mechanism, which links staff number to the insured clients to avoid work overload or low service quality. Second, all of the expenditures of the service system should be a part of social insurance funds to completely avoid budget shortage. Third, in order to divide administration and service management and to separate supervision and operation functions, a national social insurance administration should be instituted,     

The American Community Survey: general commentary on the findings from external evaluations

As part of the Census Bureau’s effort to prove the operational feasibility of the American Community Survey (ACS), the Bureau contracted with local experts to conduct comparative analyses of the 1999–2001 ACS estimates with the 2000 Census data for various test counties. One of the goals of the ACS is to replace the decennial census long form. The resulting research papers analyzed various quality measures (response rates, allocation rates, and so on), conceptual differences in the two instruments, and statistical reliability in an effort to add to our assessment of the ACS as an adequate replacement instrument for collecting long form data. This paper discusses the results of these four research efforts and presents conclusions and recommendations for further Census Bureau action and research. The quality of traditional long form data, the importance of accurate population estimates and an accurate Master Address File (MAF), and continued research on the quality of small area data are discussed.     

American Community Survey overview and the role of external evaluations

In 2010 the U.S. Census Bureau will achieve its goal of eliminating the long form sample from the decennial census and will produce its first set of five-year data products from the full sample American Community Survey (ACS). This paper provides an overview of the call for change that prompted the Census Bureau to pursue the development of a new approach to collecting socioeconomic and housing data. The paper details the evolution of the ACS from its earliest origins to its current design and describes that design in detail. The current design has benefited from external debate and consultation. Work such as that described later in this journal exemplifies the key role that external users and advisors have played, and will continue to play, in the evolution of the ACS. Over the past 10 years, the Census Bureau has undertaken research and testing to demonstrate operational feasibility and to assess survey quality. Research has also compared ACS and Census 2000 data. ACS staff are involved in survey improvement efforts and continue to confront survey challenges. In the next few years the ACS will give priority to developing user tools to aid all users in the correct interpretation of multi-year estimates. The ultimate validation of the ACS is, however, in the hands of users. Continued input from the people who are responsible for administering and evaluating programs, identifying local needs, and planning for the future will allow the ACS to grow in value and utility.     

Beyond the Castro: The Role of Demographics in the Selection of Gay and Lesbian Enclaves

Although some qualitative research has noted differences in gay and lesbian enclaves based on characteristics such as race and sex, in this article, we draw upon quantitative data from the U.S. Census to demonstrate the manner in which enclave formation is affected by the interaction of sexual orientation and other demographic characteristics (such as sex, race, age, and income). We focus our attention on enclaves located in three counties in the San Francisco Bay Area: San Francisco County, Alameda County, and Sonoma County as one example. Even though these spaces fall within close proximity to one another and share similar geographic appeal, our analyses indicate that these enclaves are far from homogenous in terms of the demographic composition of their inhabitants. These quantitative analyses provide further support to past qualitative findings, as well as highlight additional distinctions in the manner in which demographics affect enclave selection. We supplement our demographic analyses with supporting field research and interviews, further highlighting both the variation and the commonalities of these enclaves. Overall, our findings promote an expansion of the understanding how intersecting demographic characteristics affect selection of a particular enclave and what may constitute a gay enclave.     

World food resources and population: the narrowing margin

This bulletin examines the narrowing margin between global food production and population growth. Between 1950 and 1971, world grain production nearly doubled and per capita production increased 31%. During the 1970s, gains in output barely kept pace with population growth, consumption/person declined in sub-Saharan Africa and parts of Asia, food prices were volatile, and over 100 food deficit countries came to depend on the exportable surplus of North America, now the only major grain exporting region. The world fish catch levelled off in the early 1970s and beef production, still dependent mainly on grassland grazing, levelled off in the mid-1970s. With little new land left to plow, satisfying increased food demand now depends on sharp increases in yields on existing crop land. Worldwide, this effort is hampered by loss of topsoil and irrigated land, conversion of cropland to nonfarm uses, rising energy costs, inefficient agrarian structures, particularly in the Soviet Union, the falling yield response to chemical fertilizers in agriculturally advanced countries, and the emerging competition between food and agriculturally based energy crops. Green Revolution successes in some developing countries deomonstrate that, given the right inputs, 3rd world farmers can increase crop yields dramatically. Feeding the world's poor also requires more equitable income and food distribution, including a reduction in the proportion of grain and fish consumed indirectly as livestock products by the affluent. Most important in meeting food needs on a finite planet is braking population growth. The author concludes that every effort should be made to stabilize world production at abour 6 billion by 2020, rather than 10.5 billion by 2110, as is now projected by the UN.     

Comparison of Census 2000 and American Community Survey 1999–2001 Estimates: San Francisco and Tulare Counties, California

Data from the United States 2000 decennial census long form sample is compared to the U.S. Census Bureau’s fledgling American Community Survey (ACS) that was designed to replace the census long form in 2010. This article concentrates on two California counties, San Francisco and Tulare, which were part of the demonstration phase of the ACS. These counties are described and an overall comparison of the demographic, social, economic, and housing variables is presented. The project data and measures of census and survey quality such as self-response rates and nonresponse rates are displayed and discussed. Differences in the census and survey results are noted in the context of statistically significant and meaningful differences. Finally, strategies for analyzing and using ACS data are suggested.     

Reconstructing the size of the African American population by age and sex, 1930–1990

We estimate the size of the African American population in five-year age groups at census dates from 1930 to 1990 using a three-part strategy. For cohorts born after 1935, we follow the U.S. Census Bureau in using classical demographic analysis. To estimate the size of cohorts born before 1895, we use extinct-generation estimates. For remaining cohorts, we implement an age/period/cohort model of census counts. All approaches are applied to a data set in which the age distribution of deaths has been corrected for age misreporting. Results provide strong confirmation of the basic validity of Census Bureau estimates of census undercounts for African Americans while extending estimates to new cohorts and periods. Our estimates are less consistent with an historical series prepared by Coale and Rives (1973).     

An evaluation of bridging methods using race data from Census 2000

The question on race from Census 2000 was different from previous censuses because it allowed respondents to select one or more races to indicate their racial identities. Because of this change, the race data from Census 2000 are not directly comparable with data from earlier censuses. Researchers can use `bridging' methods to assign more than one race respondents to single race categories to maximize the comparability of Census 2000 race data with earlier censuses. This paper uses several bridging methods to generate race population estimates and analyzes the variability in those estimates across six single race groups.