Glutathione and Related γ-Glutamyl Compounds: Biosynthesis and Utilization

<P>Abstract copyright UK Data Service and data collection copyright owner.</P><p><strong>Background</strong><br>The <em>Labour Force Survey</em> (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 Annual Population Survey, also held at the UK Data Archive, is derived from the LFS.</p>\n\n<p>The LFS was first conducted biennially from 1973, then 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 <em>Quarterly Labour Force Survey</em> (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 available). Further information on the background to the QLFS may be found in the documentation.<br><br><strong>LFS Documentation</strong><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 title="Labour Force Survey - User Guidance" href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/methodologies/labourforcesurveyuserguidance">Labour Force Survey - User Guidance</a> pages before commencing analysis.<strong>This is especially important for users of older QLFS studies, where information and guidance in the user guide documents may have changed over time.<br></strong><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">new reweighting policy</a><a href="http://doc.ukdataservice.ac.uk/doc/8343/mrdoc/pdf/biennial_lfs_aps_reweighting_policy.pdf" target="_blank"></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><br><strong>Additional data derived from the QLFS</strong><br>The Archive also holds further QLFS series: Secure Access datasets (see below); household datasets; two-quarter and five-quarter longitudinal datasets; quarterly, annual and ad hoc module datasets compiled for Eurostat; and some additional annual Northern Ireland datasets.<br><br><strong>End User Licence and Secure Access QLFS data</strong><br>Users should note that there are two discrete versions of the QLFS. One is available under the standard End User Licence (EUL) agreement, and the other is a Secure Access version. The EUL version includes country and Government Office Region geography, 3-digit Standard Occupational Classification (SOC) and 3-digit industry group for main, second and last job (from July-September 2015, 4-digit industry class is available for main job only).<br><br>The Secure Access version contains more detailed variables relating to:</p>\n<ul>\n<li>age: single year of age, year and month of birth, age completed full-time education and age obtained highest qualification, age of oldest dependent child and age of youngest dependent child</li>\n<li>family unit and household: including a number of variables concerning the number of dependent children in the family according to their ages, relationship to head of household and relationship to head of family</li>\n<li>nationality and country of origin</li>\n<li>finer detail geography: including county, unitary/local authority, place of work, Nomenclature of Territorial Units for Statistics 2 (NUTS2) and NUTS3 regions, and whether lives and works in same local authority district, and other categories;</li>\n<li>health: including main health problem, and current and past health problems</li>\n<li>education and apprenticeship: including numbers and subjects of various qualifications and variables concerning apprenticeships</li>\n<li>industry: including industry, industry class and industry group for main, second and last job, and industry made redundant from</li>\n<li>occupation: including 5-digit industry subclass and 4-digit SOC for main, second and last job and job made redundant from</li>\n<li>system variables: including week number when interview took place and number of households at address</li>\n<li>other additional detailed variables may also be included.</li>\n</ul>\n\n<p>The Secure Access datasets (SNs 6727 and 7674) have more restrictive access conditions than those made available under the standard EUL. Prospective users will need to gain ONS Accredited Researcher status, complete an extra application form and demonstrate to the data owners exactly why they need access to the additional variables. Users are strongly advised to first obtain the standard EUL version of the data to see if they are sufficient for their research requirements.<br><br><strong>Changes to Country of Birth and Nationality variables, 2017</strong>:<br>Following a disclosure review in 2016 by the ONS Data Access Team, changes have been made to the LFS Country of Birth and Nationality variables from the July-September 2017 quarter. Four new variables have been created and four variables removed. The new groupings are consistent with those published by the Migration Statistics Unit and so should facilitate users to carry out required analysis of Country of Birth and Nationality. The variables added are: CRYOX7_EUL_Main, CRYOX7_EUL_Sub, NATOX7_EUL_Main and NATOX7_EUL_Sub. The variables removed are: CRYO7, CRYOX7, NATO7 and NATOX7.<br><br><strong>Variables DISEA and LNGLST</strong><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. An ONS Methodology section article on <a href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/methodologies/analysisofthediscontinuityinthelabourforcesurveydisabilitydataapriltojune2017tojulytoseptember2017">Analysis of the discontinuity in the Labour Force Survey disability data: April to June 2017 to July to September 2017</a> has also been published. For any queries about Dataset A08 please email <a href="mailto:Labour.Market@ons.gov.uk">Labour.Market@ons.gov.uk</a></p>\n\n<p><strong>ONS methodology reports on the Labour Force Survey, published 2019</strong>:</p>\n<ul>\n<li>A report on progress to assess potential bias in the LFS through a comparison against alternative data sources including proxy labour measures from administrative data: <a href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/methodologies/exploringtheuseofexternaldatatoassessforobservedbiasinlabourforcesurveyestimatesinterimfindings">Exploring the use of external data to assess for observed bias in Labour Force Survey estimates: interim findings</a></li>\n<li>An update on <a href="https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/employmentandemployeetypes/methodologies/progressagainstthelabourforcesurveynationalstatisticsqualityreviewrecommendations">Progress against the Labour Force Survey National Statistics Quality Review recommendations</a></li></ul><p><strong>LFS response to COVID-19</strong><br>Since April 2020, additional non-calendar quarter LFS microdata have been delivered to Government Departments and the wider research community through the ONS Secure Research Service and UK Data Service. The first additional microdata to be released covered the period February to April 2020, to coincide with Labour Market Statistical Bulletin publication on 16 June. Further guidance was also provided with the release of the February to April 2020 microdata. Please consult the documentation for full details. </p><p>Users should note that within the additional COVID-19 quarters, the pseudonymised variables Casenop and Hserialp m