Labour Force Survey Two-Quarter Longitudinal Dataset, July - December, 2005

<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> This study was deposited in 2008, as a result of the move from seasonal to calendar quarters for the QLFS, and the reweighting process to 2007-2008 population figures. It combines data from previously-available QLFS seasonal two-quarter longitudinal datasets. The depositor has advised that small revisions to the data may have been made during this process, but they should not be significant.<br>
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For the second edition (July 2015) an updated version of the data file was deposited, weighted to 2014 population figures (based on Census 2011).<br>
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<p><b>背景</b><br><i>劳动力调查（Labour Force Survey, LFS）</i>是一套独特的信息来源，采用国际通用的就业、失业及经济非活动状态定义，涵盖职业、培训、工作时长以及16岁及以上家庭成员个人特征等广泛相关主题，可为社会、经济与就业政策制定提供参考。该调查于1973年至1983年首次以两年为期开展，1984年至1991年转为年度调查，包含全年季度调查与春季季度的"补充"调查（当时数据按季度采集）。1992年起，该调查开始提供季度数据，季度样本量大致等同于此前的年度数据，此后该调查被称为<i>季度劳动力调查（Quarterly Labour Force Survey, QLFS）</i>。1994年12月，北爱尔兰的数据采集转为完整季度周期，与英国其他地区保持一致，自此QLFS覆盖全英国（不过英国数据档案馆（UK Data Archive）仍留存有部分额外的北爱尔兰年度LFS数据集）。有关QLFS背景的更多信息可参阅相关文档。<br><br><b>纵向数据</b><br>LFS会将每个样本家庭保留连续五个季度，每季度更换五分之一的样本。主调查旨在生成横截面数据，但现已将每个个体的数据进行关联，以提供纵向信息。纵向数据包含两类关联数据集，均通过加权方法调整无回应偏差。两季度数据集关联连续两轮调查的数据，而五季度数据集则关联一整年（例如2010年1月至2011年3月，含首尾时段）的全部五轮调查数据。完整的纵向数据序列可追溯至1992年冬季。通过关联记录构建纵向维度，例如可提供不同劳动力类别（就业、失业与经济非活动）间随时间变化的总流动信息，详细呈现于各类别间流动的人群情况。此外，纵向信息有助于监测政府政策的实施效果，可用于追踪受特定政策举措影响人群的后续活动与处境，并与其他人口群体进行对比。不过，此类纵向关联可能引入方法学问题，导致数据失真。英国国家统计局（Office for National Statistics, ONS）仍在对此类问题开展研究，并建议在呈现结果时需谨慎考量，必要时应在输出结果中附上相关警示。<br><br><span style="font-weight: bold;">新加权政策</span><br>根据<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);">新加权政策</a>，ONS审阅了2019年期间发布的最新人口估算数据，并决定不开展2019年LFS与年度人口调查（Annual Population Survey, APS）的加权工作。因此，下一次加权工作将于2020年进行，将纳入2019年地方人口预测数据（2020年5月发布）与2019年年中人口估算数据（2020年6月发布）。预计重新加权后的劳动力市场汇总数据与微观数据将于2020年末/2021年初发布。<br><br><b>LFS文档</b><br>档案馆配套LFS数据集的文档主要包含各用户指南卷的最新版本，以及对应年度的相应问卷。但ONS会定期更新用户指南卷，因此建议用户在开展分析前，先查阅ONS的<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>这一点对于老旧QLFS数据集的使用者尤为重要，因为用户指南中的信息与指引可能已随时间发生变化。</b><br><br><b>源自QLFS的额外数据</b><br>档案馆还留存有更多QLFS系列数据：最终用户许可（End User Licence, EUL）季度数据、安全访问数据集、家庭数据集、为欧盟统计署（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><br><b>变量DISEA与LNGLST</b><br>因2017年4月至6月与2017年7月至9月间存在明显数据断裂，ONS曾暂停的A08数据集（残疾人劳动力市场状况）现已恢复可用。鉴于此次明显的数据断裂及现阶段调查结果尚不明确，在对2017年4月至6月与后续时间段的数据进行比较时需谨慎。同时用户需注意，该估算值未经过季节性调整，因此季度间的部分变化可能源于季节性因素。ONS将于2018年11月发布2018年7月至9月的估算数据时，就历史数据比较的进一步建议作出说明。一篇解释目前已开展的质量保证调查的文章可在ONS方法学<a href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/methodologies/analysisofthediscontinuityinthelabourforcesurveydisabilitydataapriltojune2017tojulytoseptember2017" target="_blank">网页</a>获取。若对A08数据集有任何疑问，请发送邮件至[e-mail]。<br></p><p><span style="font-weight: bold;">2021年与2022年数据文件的职业数据</span><br></p><p>ONS发现其多项调查在2021年和2022年数据文件中存在部分职业数据采集问题。尽管ONS估算整体影响较小，但这将影响部分细分（四位数字标准职业分类（Standard Occupational Classification, SOC））职业的细分数据及其衍生数据的准确性。更多信息可参阅ONS2023年7月11日发布的文章：<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);">《英国ONS劳动力调查中错编码职业数据的修订：2021年1月至2022年9月》</a>。</p><p><span style="font-weight: bold;">2022年加权</span></p><p>用于最新LFS估算的人口总数采用基于2021年模式的实时信息（Real Time Information, RTI）数据的增长率预测值，涵盖英国、欧盟及非欧盟人口。因此，用于LFS的总人口未考虑2021年6月以来的移民、出生率、死亡率等变化，故而水平估算值可能高估或低估真实数值，使用时需谨慎。不过，比率估算值仍将保持稳健。</p>本数据集于2008年存档，起因是QLFS从季节性季度转为日历季度，并将加权流程调整至2007-2008年人口数据。该数据集整合了此前可用的QLFS季节性两季度纵向数据集。存档方提示，在此过程中可能对数据进行了小幅修订，但修订幅度不应过大。<br><br>2015年7月推出的第二版数据文件为更新版本，加权至2014年人口数据（基于2011年人口普查结果）。<br><br>