Labour Force Survey Two-Quarter Longitudinal Dataset, September 1993 - February 1994

<p><b>Background</b><br>
The <i>Labour Force Survey</i> (LFS) is a unique source of information using international definitions of employment and unemployment and economic inactivity, together with a wide range of related topics such as occupation, training, hours of work and personal characteristics of household members aged 16 years and over. It is used to inform social, economic and employment policy. The LFS was first conducted biennially from 1973-1983. Between 1984 and 1991 the survey was carried out annually and consisted of a quarterly survey conducted throughout the year and a 'boost' survey in the spring quarter (data were then collected seasonally). From 1992 quarterly data were made available, with a quarterly sample size approximately equivalent to that of the previous annual data. The survey then became known as the <i>Quarterly Labour Force Survey</i> (QLFS). From December 1994, data gathering for Northern Ireland moved to a full quarterly cycle to match the rest of the country, so the QLFS then covered the whole of the UK (though some additional annual Northern Ireland LFS datasets are also held at the UK Data Archive). Further information on the background to the QLFS may be found in the documentation.<br>
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<b>Longitudinal data</b><br>
The LFS retains each sample household for five consecutive quarters, with a fifth of the sample replaced each quarter. The main survey was designed to produce cross-sectional data, but the data on each individual have now been linked together to provide longitudinal information. The longitudinal data comprise two types of linked datasets, created using the weighting method to adjust for non-response bias. The two-quarter datasets link data from two consecutive waves, while the five-quarter datasets link across a whole year (for example January 2010 to March 2011 inclusive) and contain data from all five waves. A full series of longitudinal data has been produced, going back to winter 1992. Linking together records to create a longitudinal dimension can, for example, provide information on gross flows over time between different labour force categories (employed, unemployed and economically inactive). This will provide detail about people who have moved between the categories. Also, longitudinal information is useful in monitoring the effects of government policies and can be used to follow the subsequent activities and circumstances of people affected by specific policy initiatives, and to compare them with other groups in the population. There are however methodological problems which could distort the data resulting from this longitudinal linking. The ONS continues to research these issues and advises that the presentation of results should be carefully considered, and warnings should be included with outputs where necessary.<br><br><span style="font-weight: bold;">New reweighting policy</span><br>Following the <a href="http://doc.ukdataservice.ac.uk/doc/8343/mrdoc/pdf/biennial_lfs_aps_reweighting_policy.pdf" target="_blank" style="background-color: rgb(255, 255, 255);">new reweighting policy</a> ONS has reviewed the latest population estimates made available during 2019 and have decided not to carry out a 2019 LFS and APS reweighting exercise. Therefore, the next reweighting exercise will take place in 2020. These will incorporate the 2019 Sub-National Population Projection data (published in May 2020) and 2019 Mid-Year Estimates (published in June 2020). It is expected that reweighted Labour Market aggregates and microdata will be published towards the end of 2020/early 2021.<br>
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<b>LFS Documentation</b><br>
The documentation available from the Archive to accompany LFS datasets largely consists of the latest version of each user guide volume alongside the appropriate questionnaire for the year concerned. However, volumes are updated periodically by ONS, so users are advised to check the latest documents on the ONS <a href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/methodologies/labourforcesurveyuserguidance" title="Labour Force Survey - User Guidance">Labour Force Survey - User Guidance</a> pages before commencing analysis. <b>This is especially important for users of older QLFS studies, where information and guidance in the user guide documents may have changed over time.</b><br>
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<b> Additional data derived from the QLFS</b><br>
The Archive also holds further QLFS series: End User Licence (EUL) quarterly data; Secure Access datasets; household datasets; quarterly, annual and ad hoc module datasets compiled for Eurostat; and some additional annual Northern Ireland datasets. <br>
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<b>Variables DISEA and LNGLST</b><br>
Dataset A08 (Labour market status of disabled people) which ONS suspended due to an apparent discontinuity between April to June 2017 and July to September 2017 is now available. As a result of this apparent discontinuity and the inconclusive investigations at this stage, comparisons should be made with caution between April to June 2017 and subsequent time periods. However users should note that the estimates are not seasonally adjusted, so some of the change between quarters could be due to seasonality. Further recommendations on historical comparisons of the estimates will be given in November 2018 when ONS are due to publish estimates for July to September 2018. <br>
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An article explaining the quality assurance investigations that have been conducted so far is available on the <a href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/methodologies/analysisofthediscontinuityinthelabourforcesurveydisabilitydataapriltojune2017tojulytoseptember2017" target="_blank">ONS Methodology</a> webpage. For any queries about Dataset A08 please email [e-mail].<br>
</p><p><span style="font-weight: bold;">Occupation data for 2021 and 2022 data files</span><br></p><p>The ONS has identified an issue with the collection of some occupational data in 2021 and 2022 data files in a number of their surveys. While they estimate any impacts will be small overall, this will affect the accuracy of the breakdowns of some detailed (four-digit Standard Occupational Classification (SOC)) occupations, and data derived from them. Further information can be found in the ONS article published on 11 July 2023: <a title="Revision of miscoded occupational data in the ONS Labour Force Survey, UK: January 2021 to September 2022" href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/articles/revisionofmiscodedoccupationaldataintheonslabourforcesurveyuk/january2021toseptember2022" style="background-color: rgb(255, 255, 255);">Revision of miscoded occupational data in the ONS Labour Force Survey, UK: January 2021 to September 2022</a>.</p><p><span style="font-weight: bold;">2022 Weighting</span></p><p>The population totals used for the latest LFS estimates use projected growth rates from Real Time Information (RTI) data for UK, EU and non-EU populations based on 2021 patterns. The total population used for the LFS therefore does not take into account any changes in migration, birth rates, death rates, and so on since June 2021, and hence levels estimates may be under- or over-estimating the true values and should be used with caution. Estimates of rates will, however, be robust.</p> For the second edition (June 2004), the depositor supplied a re-weighted version of the data file. The re-weighting has been done to bring LFS data in line with the population estimates from the 2001 Census. Some variables have been removed, some added and others renamed - please see READ file for details.

<p><b>背景</b><br>
劳动力调查（Labour Force Survey，LFS）是一项独特的信息来源，采用就业、失业及经济不活跃的国际定义，涵盖职业、培训、工作时长及16岁及以上家庭成员个人特征等广泛相关主题。它用于为社会、经济及就业政策提供信息支持。LFS最初于1973-1983年每两年开展一次；1984至1991年间改为每年开展，包含全年每季度调查及春季季度的“补充”调查（数据按季节收集）；1992年起开始提供季度数据，季度样本量约相当于此前年度数据规模，此后该调查被称为季度劳动力调查（Quarterly Labour Force Survey，QLFS）。1994年12月起，北爱尔兰的数据收集转为完整季度周期，以与英国其他地区保持一致，因此QLFS覆盖全英国（不过英国数据档案库还存有部分额外的北爱尔兰年度LFS数据集）。关于QLFS背景的更多信息可查阅相关文档。<br>
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<b>纵向数据</b><br>
LFS将每个样本家庭保留五个连续季度，每季度替换五分之一样本。主调查旨在生成横截面数据，但如今已将个体数据关联起来以提供纵向数据。纵向数据包含两种关联数据集，均采用加权方法调整非响应偏差：两季度数据集关联连续两个波次的数据；五季度数据集关联一整年（例如2010年1月至2011年3月，含首尾）的数据，涵盖所有五个波次。完整的纵向数据系列可追溯至1992年冬季。通过关联记录构建纵向维度，可获取不同劳动力类别（就业、失业、经济不活跃）间随时间的总流动情况，从而详细了解类别间转移的人群。此外，纵向信息有助于监测政府政策效果，可用于跟踪受特定政策举措影响人群的后续活动及状况，并与人口中其他群体进行比较。然而，纵向关联可能导致数据失真的方法论问题，ONS持续研究这些问题，并建议谨慎呈现结果，必要时在输出中加入警示。<br><br><span style="font-weight: bold;">新重加权政策</span><br>遵循<a href="http://doc.ukdataservice.ac.uk/doc/8343/mrdoc/pdf/biennial_lfs_aps_reweighting_policy.pdf" target="_blank" style="background-color: rgb(255, 255, 255);">新重加权政策</a>，ONS已审查2019年期间发布的最新人口估计数，并决定不开展2019年LFS及APS重加权工作。因此，下一次重加权工作将于2020年进行，将纳入2019年地方人口投影数据（2020年5月发布）及2019年年中估计数（2020年6月发布）。预计重加权后的劳动力市场汇总数据及微观数据将于2020年末/2021年初发布。<br>
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<b>LFS文档</b><br>
档案库提供的LFS数据集配套文档主要包括各用户指南卷的最新版本及对应年份的问卷。但ONS会定期更新这些卷册，因此建议用户在开始分析前，查阅ONS <a href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/methodologies/labourforcesurveyuserguidance" title="Labour Force Survey - User Guidance">劳动力调查-用户指南</a>页面的最新文档。<b>这对旧QLFS研究的用户尤为重要，因其用户指南文档中的信息及指导可能随时间变化。</b><br>
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<b>QLFS衍生的附加数据</b><br>
档案库还存有更多QLFS系列：终端用户许可（End User Licence，EUL）季度数据、安全访问数据集、家庭数据集、为欧盟统计局（Eurostat）编制的季度、年度及临时模块数据集，以及部分额外的北爱尔兰年度数据集。 <br>
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<b>变量DISEA与LNGLST</b><br>
因2017年4-6月与2017年7-9月间存在明显不连续性而被ONS暂停的数据集A08（残疾人劳动力市场状况）现已可用。由于此明显不连续性及现阶段调查无定论，对比2017年4-6月与后续时间段数据时需谨慎。但用户需注意，估计数未进行季节性调整，因此季度间变化可能部分源于季节性因素。关于估计数历史对比的进一步建议将于2018年11月ONS发布2018年7-9月估计数时给出。 <br>
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解释迄今已开展质量保证调查的文章可在<a href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/methodologies/analysisofthediscontinuityinthelabourforcesurveydisabilitydataapriltojune2017tojulytoseptember2017" target="_blank">ONS方法论</a>网页查阅。关于数据集A08的任何疑问，请发送邮件至[e-mail]。<br>
</p><p><span style="font-weight: bold;">2021及2022年数据文件的职业数据</span><br></p><p>ONS发现其多项调查中2021及2022年数据文件的部分职业数据收集存在问题。尽管整体影响估计较小，但这会影响部分详细（四位编码标准职业分类（Standard Occupational Classification，SOC））职业的细分准确性及衍生数据。更多信息可查阅ONS于2023年7月11日发布的文章：<a href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/articles/revisionofmiscodedoccupationaldataintheonslabourforcesurveyuk/january2021toseptember2022" style="background-color: rgb(255, 255, 255);">英国国家统计局劳动力调查中编码错误的职业数据修订：2021年1月至2022年9月</a>。</p><p><span style="font-weight: bold;">2022年加权</span></p><p>最新LFS估计数所用人口总数基于2021年模式，采用英国、欧盟及非欧盟人口的实时信息（Real Time Information，RTI）数据投影增长率。因此，LFS所用总人口未考虑2021年6月以来移民、出生率、死亡率等变化，故水平估计数可能高估或低估真实值，需谨慎使用；但比率估计数仍具稳健性。</p> 对于第二版（2004年6月），数据提交方提供了数据文件的重加权版本，旨在使LFS数据与2001年人口普查的人口估计数保持一致。部分变量被移除、新增或重命名——详情请查阅READ文件。