Evaluation, Revision and Extension of Ethnic Population Projections - NewETHPOP

本项目旨在了解和预测联合王国人口在国家和国家以下各级的种族转变。种族转变是人口构成的变化，从以白种英国人为主转向更加多样化。在2001-2011十年间，由于大量移民、生育率的提高和死亡率的降低，英国人口强劲增长。英国国家统计局(ONS)和利兹大学都估计了组成英国人口的16个民族在2001年的增长或下降。2011年人口普查结果显示，两个团队都高估了英国白人人口的增长，低估了少数民族人口的增长。我们地方当局预测的2011年人口与人口普查之间的巨大差异表明，对国内移民的预测不准确。我们建议与国家统计局密切合作，作为我们的第一个外部合作伙伴，利用关于本十年后几年的新数据和新方法，对年中族裔人口及其变化部分进行新的估计，以确保2011年的估计与人口普查相一致。这将涉及使用人口核算理论和一种称为迭代比例拟合的调整技术，以生成2001至2011年间完全一致的一套族裔人口估计数。我们将在国家和地方范围内研究族裔人口人口比率的发展(生育率、死亡率、国内移徙和国际移徙)。构成部分摘要指标和具体年龄比率的十年时间序列将为模拟未来的预测假设提供基础。在我们的主要预测中，我们将使假设与基于国家统计局2012年的本金预测保持一致。国家假设将需要转换为种族群体和地方规模。经过修订的10年特定族裔构成比率将使我们能够研究国家和地方人口趋势之间的关系。此外，我们还将分析地方当局内部迁移的一致时间序列。在这个阶段，我们不能确定每个民族的国家-地方关系将如何建模，但我们将能够使用时间序列来测试我们的模型。当然，所有对未来人口的预测都是不确定的。因此，我们将致力于衡量组成费率的不确定性。误差分布可以用来通过随机投影来构造未来总体的概率分布，以便我们可以定义围绕我们的投影的置信度区间。预测的使用者总是对组成部分假设对未来人口的影响感兴趣。我们将运行一套参考预测，以估计国际移徙假设(移民减去移民的净影响)、国内移徙假设(迁入减去迁出的净影响)、生育率假设与更替水平的比较、死亡率假设与不变的死亡率假设的影响的大小和方向，最后是初始年龄分布的影响(即人口潜力)。项目的输出将是一组关于研究各个方面的技术报告、提交同行审查的期刊论文，以及一个用户可通过网络获得的预测输入和产出的数据库。我们的第二个外部合作伙伴Edge Analytics将对人口统计数据进行质量保证。他们还将帮助将这些信息传播给地方政府用户，这些用户希望在他们自己的种族预测中使用这些信息。总而言之，该项目将展示如何在理论上精炼的人口模型中使用广泛的次要数据来源，为我们提供更可靠的英国人口种族构成变化的图景。

SummaryThis project aims to understand and to forecast the ethnic transition in the United Kingdom's population at national and subnational levels. The ethnic transition is the change in population composition from one dominated by the White British to much greater diversity. In the decade 2001-2011 the UK population grew strongly as a result of high immigration, increased fertility and reduced mortality. Both the Office for National Statistics (ONS) and Leeds University estimated the growth or decline in the sixteen ethnic groups making up the UK's population in 2001. The 2011 Census results revealed that both teams had over-estimated the growth of the White British population and under-estimated the growth of the ethnic minority populations. The wide variation between our local authority projected populations in 2011 and the Census suggested inaccurate forecasting of internal migration. We propose to develop, working closely with ONS as our first external partner, fresh estimates of mid-year ethnic populations and their components of change using new data on the later years of the decade and new methods to ensure the estimates agree in 2011 with the Census. This will involve using population accounting theory and an adjustment technique known as iterative proportional fitting to generate a fully consistent set of ethnic population estimates between 2001 and 2011.We will study, at national and local scales, the development of demographic rates for ethnic group populations (fertility, mortality, internal migration and international migration). The ten year time series of component summary indicators and age-specific rates will provide a basis for modelling future assumptions for projections. We will, in our main projection, align the assumptions to the ONS 2012-based principal projection. The national assumptions will need conversion to ethnic groups and to local scale. The ten years of revised ethnic-specific component rates will enable us to study the relationships between national and local demographic trends. In addition, we will analyse a consistent time series of local authority internal migration. We cannot be sure, at this stage, how the national-local relationships for each ethnic group will be modelled but we will be able to test our models using the time series. Of course, all future projections of the population are uncertain. We will therefore work to measure the uncertainty of component rates. The error distributions can be used to construct probability distributions of future populations via stochastic projections so that we can define confidence intervals around our projections. Users of projections are always interested in the impact of the component assumptions on future populations. We will run a set of reference projections to estimate the magnitude and direction of impact of international migrations assumptions (net effect of immigration less emigration), of internal migration assumptions (the net effect of in-migration less out-migration), of fertility assumptions compared with replacement level, of mortality assumptions compared with no change and finally the effect of the initial age distribution (i.e. demographic potential).The outputs from the project will be a set of technical reports on each aspect of the research, journal papers submitted for peer review and a database of projection inputs and outputs available to users via the web. The demographic inputs will be subject to quality assurance by Edge Analytics, our second external partner. They will also help in disseminating these inputs to local government users who want to use them in their own ethnic projections. In sum, the project will show how a wide range of secondary data sources can be used in theoretically refined demographic models to provide us with a more reliable picture of how the UK population is going to change in ethnic composition.