Labour Force Survey Five-Quarter Longitudinal Dataset, October 1997 - December 1998

<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>
<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" target="_blank">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></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 five-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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<p><b>背景</b><br>
劳动力调查（Labour Force Survey，LFS）是采用就业、失业及经济不活跃的国际定义，同时涵盖职业、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的独特信息来源。它用于为社会、经济及就业政策提供参考依据。LFS最初于1973年至1983年期间每两年开展一次。1984年至1991年间，该调查改为每年进行，由全年的季度调查和春季季度的“补充”调查组成（当时数据按季节收集）。自1992年起，季度数据开始对外提供，季度样本量大致相当于此前的年度数据量。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的季度周期，以与英国其他地区保持一致，因此QLFS随后覆盖了整个英国（不过英国数据档案库也保存了一些额外的北爱尔兰年度LFS数据集）。有关QLFS背景的更多信息可在文档中找到。<br>
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<b>纵向数据</b><br>
LFS将每个样本家庭连续保留五个季度，每季度替换五分之一的样本。主要调查旨在生成横截面数据，但现在已将每个个体的数据关联起来以提供纵向信息。纵向数据包含两种关联数据集，均采用加权方法调整无应答偏差。两季度数据集关联连续两个波次的数据，而五季度数据集则跨一整年关联（例如2010年1月至2011年3月，含首尾），并包含所有五个波次的数据。完整的纵向数据系列已生成，可追溯至1992年冬季。将记录关联以创建纵向维度，例如可提供不同劳动力类别（就业、失业及经济不活跃）之间随时间变化的总流动信息。这将详细呈现不同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，并将其与人口中的其他群体进行比较。然而，这种纵向关联可能导致数据失真的方法学问题。英国国家统计局（ONS）持续研究这些问题，并建议应谨慎考虑结果的呈现方式，必要时在输出结果中加入警告说明。<br><br>
<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册的最新版本以及相关年份的对应问卷。不过，英国国家统计局（ONS）会定期更新卷册，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" target="_blank">劳动力调查——用户指南</a>页面上的最新文档。<b>这对于旧版QLFS研究的用户尤为重要，因为用户指南文档中的信息和指导可能随时间发生变化。</b><br></p><p><span style="font-weight: bold;">2021及2022年数据文件中的职业数据</span><br></p><p>英国国家统计局（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。尽管他们估计总体影响较小，但这将影响部分详细（四位代码标准职业分类（Standard Occupational Classification，SOC））职业的分类准确性及其衍生数据。更多信息可参见ONS于2023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);">英国国家统计局劳动力调查中错误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年加权处理</span></p><p>最新LFS估计所用的人口总数采用基于2021年模式的英国、欧盟及非欧盟人口实时信息（Real Time Information，RTI）数据预测增长率。因此，LFS所用的总人口未考虑2021年6月以来移民、出生率、死亡率等方面的任何变化，故水平估计值可能高估或低估真实值，使用时需谨慎。不过，比率估计值将保持稳健。</p> 本研究于2008年存档，原因是QLFS从季节季度转为日历季度，以及采用2007-2008年人口数据进行重新加权。它整合了此前可用的QLFS季节性五季度纵向数据集的数据。存档者表示，此过程中可能对数据进行了小幅修订，但影响不显著。<br><br>