Labour Force Survey
The Labour Force Survey (LFS) is a
quarterly sample survey of households living at private addresses in the United Kingdom.
Its purpose is to provide information on the UK labour market that can then
be used to develop, manage, evaluate and report on labour market policies. It
is conducted by the Office for National Statistics.
The National Statistics
web site contains some detailed
information about the survey.
Recent LFS news
1. ONS user guides updated
An updated version of the Labour Force Survey longitudinal user guide has been published by the Office for National Statistics. It can be obtained from the ONS Labour Force Survey - User Guidance web page. Some of the other LFS user guide volumes have also been updated for 2011 and are available from the same web page.
2. ID variables on the Quarterly Labour Force Survey datasets
a. End-User Licence (EUL) files
QLFS January - March 2011 (Study Number 6782)
The JM11 QLFS data files contain new ID variables/numbers which are designed to improve the confidentiality of respondents, which has some impact on the way in which the data can be used. The new identifiers are:
CASENOP - ‘Case Identifier - pseudoanonymised’
HSERIALP - ‘Number uniquely identifies a household - pseudoanonymised’
These ID numbers are designed to permit users to link household members together, but not to link across waves to create their own longitudinal datasets (users who wish to do this should use the LFS longitudinal files). The household identifier (hserialp) is an identifier which starts at 1 and simply counts up. Common values of this variable across waves no longer indicate that the case is from the same household. The numbers are no longer based on administrative data, and many of these administrative variables have been removed for reasons of confidentiality. Accordingly, previous guidance on how to generate person and household identifiers from these administrative variables has been superceded. It should still be possible to combine datasets in order to increase sample size as variables indicating which wave of the survey the respondent is in and when the respondent entered are still present. However, it is no longer possible to check that individual cases have not been duplicated as a result of failures in the merge process. It is still possible to use the data to identify household membership using the hserialp variable. However, users are reminded that when undertaking household analysis the most suitable data for household level analysis or analyses which involve household context are the household LFS files. All future QLFS datasets will contain these two new identifier variables. A variable called QUOTAP is also available which is the ‘stint number where interview took place - pseudoanonymised’
QLFS April-June 2009-October-December 2010 - these data files contain a new ID number (IDREF) which preceded the new ID variables for the January-March 2011 dataset (see above). IDREF was designed to improve the confidentiality of respondents, which has some impact on the way in which the data can be used. IDREF does not allow linkage between quarters (nor do Casenop and HserialP – see notes above). Please note that there is no household identifier on these datasets.
QLFS 2001-2009 - there are no changes to the ID variables in these QLFS datafiles – they should contain the original QLFS identifier variables (caseno, add, quota etc).
b. Special Licence (SL)
All Special Licence QLFS datasets should still contain the original ID variables (caseno, add, quota etc) so they are not affected by the above changes.
3. Secure Data Service Access
LFS datasets are now available from the Secure Data Service (SDS). These datasets are more detailed version of existing data available through ESDS. To find out more about the content of these datasets view the online catalogue records. Before applying for access researchers should read through the catalogue records to determine if the data are suitable for their research and whether less detailed versions of the data are available and could be used instead. More information about the SDS can be found on the Secure Data Service website.
4. In accordance with EU regulations the LFS has moved from Seasonal to Calendar quarters. As a result of this process a number of variables have been dropped from the Calendar datasets. A page which lists each calendar dataset with the corresponding seasonal datasets is now available, together with more information about the changes.
Unfortunately the LFS User Guides do not reflect the changes. As a result you will find that certain variables noted in the User Guides as being present in the datasets are not actually in the datasets.
5. Change to coding of missing values for household series From the April-June 2010 household dataset onwards
Users should note that all missing values in the data have been set to one '-10' “No answer/Does not apply” category instead of the previous separate '-8' “No answer” and '-9' “Does not apply” categories. The ONS has introduced a new imputation process for the LFS household datasets and it has thus been necessary to code the missing values into one new combined category ('-10'), to avoid over-complication. The '-10' categorisation is in line with the Annual Population Survey household series. The change also applies to LFS household data back to April-June 1997 (currently being updated at the UK Data Archive), to ensure continuity for analytical purposes. The change only applies to the household data, and there are no current plans to extend it to other LFS series.
6. Labour Force Survey (LFS) Reweighting Project 2009
In 2009, the Office for National Statistics (ONS) undertook a reweighting project, whereby LFS data were reweighted using population estimates for 2009. As a result, reweighted editions of QLFS datasets from the July-September 2006 quarter onwards have been deposited at the ESDS. Users should note that quarters prior to July-September 2006 will remain weighted to the 2007-2008 population figures used for the previous LFS reweighting project conducted in 2007. Further information about the 2009 reweighting project is included in the documentation for the updated datasets.
7. Continuous age
and 4-digit SOC occupation variables are now included in the reweighted LFS
calendar datasets.
In autumn 2007, the Office for National
Statistics (ONS) began an assessment of how much detail could be retained on
government surveys which were released to users under an End User Licence. During
this period, a number of variables were removed from the LFS datasets or replaced
by recoded variables. These included the removal of the continuous age variable
(AGE) (replaced with banded age) and the 4 digit SOC code for main occupation.
In 2007, the ONS undertook a reweighting project, whereby LFS data were reweighted using
population estimates for 2007-2008. As a result, reweighted editions of LFS
back to 1992 were deposited at ESDS during 2008.
The following variables are now once
again available in the reweighted LFS data:
the single year of age variable (AGE)
4-digit unit SOC for main occupation
Only calendar datasets have been reweighted to 2007-2008 figures. The seasonal datasets have now been withdrawn from the ESDS.
8. Quarterly Labour
Force Survey Eurostat datasets are now available from ESDS. Eurostat co-ordinates
information from labour force surveys in the European Union (EU) member states
in order to assist the EU in such matters as the allocation of the Social Fund.
The Quarterly Labour Force Survey Eurostat Datasets form the UK component of
the European Union Labour Force Survey (EULFS), and consist of a subset of core
variables from the UK QLFS alongside primary and secondary derived variables
computed by Eurostat from the core variables supplied. Data is available for
a number of quarters.
9. In accordance
with EU regulations, the LFS moved from seasonal (spring, summer, autumn, winter)
quarters to calendar quarters (January-March, April-June, July-September, October-December)
in 2006. The last seasonal quarter dataset issued was the Quarterly Labour Force
Survey, December 2005 - February 2006 (SN 5356) and the first calendar quarter
dataset was the Quarterly Labour Force Survey, January - March, 2006 (SN 5369).
Users should note that there is some overlap between these two datasets. ONS
have produced a limited series of historical LFS datasets on a calendar-quarterly
basis. This will allow users to make meaningful comparisons of labour market
statistics from the LFS microdata over time. Further information on the seasonal
to calendar quarter change and its impact on LFS data may be found in the following
online article:
Madouros, V. (2006) Impact
of the LFS switch from seasonal to calendar quarters: an overview of the switch
of the LFS to calendar quarters and the potential effects of this change on
users, London: ONS.
10. The LFS Annual
Local Area Data Series and the Unitary Authority/Local Authority (UA/LA series)
have been withdrawn on instruction from ONS, due to confidentiality issues.
ONS have released the following information:
"ONS and its predecessors have always offered an assurance of confidentiality
to potential respondents in its surveys. Databases released for analysis by
outside bodies have always been anonymised to ensure that users could not identify
any respondent with the information given. However advances in technology and
software has made it easier to link survey records to either other survey files
or other administrative or commercial databases. Although the risk for most
respondents is very small, there remains a risk of identification for people
with unusual combinations of personal circumstances. Thus the release outside
the central government statistical services of social survey databases with
small area identifiers, alongside a national database with detailed coding,
has now been ceased."
This affects ESDS holdings in the
following ways.
1. Series 33309 - Quarterly Labour Force Survey: Unitary Authorities/Local Authorities
Studies 4160-4163,4174,4207,4305-4314,4325-4336,4372 and 4418 withdrawn
2. Series 33286 - Quarterly Labour
Force Survey: Local Area Data
Only the Annual Local Area Data studies
are affected, which means the following studies are withdrawn:
- SN:4321 Quarterly Labour Force Survey Annual Local Area Data, 1999-2000
- SN:4116 Quarterly Labour Force Survey Annual Local Area Data, 1998-1999
- SN:3965 Quarterly Labour Force Survey Annual Local Area Data, 1997-1998
- SN:3812 Quarterly Labour Force Survey Annual Local Area Data, 1996-1997
- SN:3653 Quarterly Labour Force Survey Annual Local Area Data, 1995-1996
- SN:3624 Quarterly Labour Force Survey Annual Local Area Data, 1994-1995
The quarterly Local Area data (LAD/TEC) studies, which
are also part of Series 33286, are not affected and can be supplied to users
as normal.
Recent data
