Introduction to the key large-scale government surveys Jo Wathan, Paul Norman & Angela Dale ESDS Government Centre for Census and Survey Research (CCSR) University of Manchester

Our mission… Intro to Economic and Social Data Service (ESDS) and how we can help you. What data is available, how it can be used in research Indication of good practice Registration, access, support services/resources Short hands-on session with real data

ESDS Government One of four specialist services of ESDS. ESDS is a new national data service (since Jan 03) –ESDS Government –ESDS Longitudinal –ESDS Qualidata –ESDS International ESDS Government provides access and user support for key large-scale government surveys such as Labour Force Survey and General Household Survey Access remains via the UKDA

ESDS Government - some of the things we do! Helpdesk Survey pages incl. how to get started Online guides – SPSS, STATA, Weighting, Employment Research, Health Research User Group seminars (data users and data creators) Publications Database Derived variables - consistent over time - consistent with Census Teaching datasets Training

Which surveys? UK or GB surveys General Household Survey Labour Force Survey Family Resources Survey Expenditure and Food Survey (previously the National Food Survey and Family Expenditure Survey) ONS Omnibus Survey National Travel Survey Time Use Survey Life & Times/Young Peoples Social Attitudes British Crime Survey /Scottish Crime Survey British Social Attitudes /Scottish Social Attitudes/ Northern Ireland Health Survey for England/Wales/Scotland Survey of English Housing (England only)

Microdata

QUALITY OF DATA (1) Two main data collectors: –Office for National Statistics (ONS) –National Centre for Social Research (NatCen) Both have considerable experience –ONS Social Surveys started in 1941 –Natcen founded in 1969 (as SCPR) Permanent panels of highly trained field interviewers Management and Quality Checking (Relatively) high response rates – but falling Widespread use by secondary analysts

QUALITY OF DATA (2) Example of GHS data collection

What would you use the data for? Straightforward secondary analysis –To assess theoretical accounts –To quantify characteristics or behaviours –To challenge official views –To apply alternative definitions Context to your own primary research –Your research could be quantitative or qualitative –To assess the national context of an area study –To assess whether your sample is typical –To assess the scale of behaviours

Practical research uses of the data Looking at change over time Look at sub-populations Using the flexibility of the data to look at alternative definitions Looking within households

Change over time

Secondary analysis: change over time among sub-populations Marmot, M (2003)

Using successive cross- sectional data over time Pros… Reasonable amount of comparability Can pool years/quarters Data is representative at each time point Good at looking at impacts on groups Cons… Limits to continuity in the data (e.g. ethnic) Cannot establish individual change

Looking at small populations Only the Samples of Anonymised Records have larger sample sizes Many surveys with 10+k respondents –Permits minority groups to be represented –Rare subpopulations sample size may be too small… can consider combining years if appropriate

Survey data is subject to sampling error! Example: Pregnancy and Employment Using General Household Survey data alone there are only 168 pregnant women aged % Confidence interval for % pregnant women economically inactive 34.2 – 49.1% Combined 3 years data to obtain sample of 465 pregnant women Confidence interval using 3 years data: 34.9 – 43.9% Combining datasets to increase sample size

Use the hierarchy to… Better describe the household Describe the household context of an individual Look at intra-household differences (& sameness)

Source: Richard Dickens, Paul Gregg and Jonathan Wadsworth (2000) New Labour and the Labour Market, CMPO Working Paper Series 00/19 Table 5

Using the flexibility of the data to look at alternative definitions What are hours worked? Is it just paid work? Or unpaid as well? Hours usually worked, or actually worked last week? In main job, or in any job? What about students? Overtime – paid? Overtime – unpaid? Lunch hours? Do non-workers work zero hours or should they be excluded?

Choosing a survey for research Which surveys cover your main topic? Which other topics are you interested in? Measurement over time Geography Respondents – whole household, children? Sample size

Using the data in teaching Methods courses –Using the data in a hands on manner –Using substantive exemplars to demonstrate a methodological point –Using the surveys as methodological exemplars Substantive courses –Making your point using data –Integrating methods into substantive courses Teaching datasets –General Household Survey –Labour Force Survey –British Crime Survey –Health Survey for England

Documentation youll need: Questionnaire Code book of Variables Description of Derived Variables Definitions Methodology including Sampling method Response achieved Population base Published reports Unless you can track the variable back to the question asked, and work out who it was asked of, you dont understand the data!

Published report (1)

Documentation - GHS Questionnaire

Survey year : 2000/05 Variable Name : ECSTILO Variable Label : ECON STAT LST WK - ILO UNEMPLOYMENT DEF Topic : Employment Population : Adults Standard/trailer : Standard Hhld/indiv.level : Individual Range : 1 to 10 Missing values : -6, -8 Priority coded : Y Program : S Date written : Date last amended : VALUE LABELS ECSTILO ( -8 ) NA, ECSTA NOT KNOWN ( -6 ) UNDER 16, MS ( 1 ) WORKING (INCL UNPAID FW) ( 2 ) GOVT SCH WTH EMP ( 3 ) GOVT SCH AT COLL ( 4 ) UNEMP (ILO DEF) ( 5 ) OTHER UNEMPLOYED ( 6 ) PERM UNABLE WORK ( 7 ) RETIRED ( 8 ) KEEPING HOUSE ( 9 ) STUDENT ( 10 ) OTHER ECON INACT derivation : IF (SCHEDTYP EQ 3 OR AGE LT 16) = -6 ELSEIF (TRNCHKA EQ 3) = 1 ELSEIF (TRNCHKA EQ 1) = 2 ELSEIF (TRNCHKA EQ 2) = 3 ELSEIF (UNPDWKR EQ 1) = 1 ELSEIF (TRNCHKA EQ 4) = 4 ELSEIF (TRNCHKA EQ 5) IF (ABLESTRT EQ 1) = 4 ELSEIF (ABLESTRT EQ 2) = 5 ELSE = -8 ELSEIF (TRNCHKA EQ 6) IF (LOOKWORK EQ -8 OR ABLSTRT EQ -8) = -8 ELSEIF (LOOKWORK EQ 1 AND ABLESTRT EQ 1) = 4 ELSE = 5 ELSEIF (TRNCHKA EQ 7) IF (ACTIVITY EQ 2) = 6 ELSEIF (WANTAJOB EQ -8 OR NABLSTRT EQ -8 OR NLOOKWRK EQ -8) = -8 ELSEIF (WANTAJOB EQ -9) = 7 ELSEIF (NABLSTRT EQ 1 AND NLOOKWRK EQ 1) = 4 ELSEIF (ACTIVITY EQ 3) = 7 ELSEIF (ACTIVITY EQ 4) = 8 ELSEIF (ACTIVITY EQ 5) = 10 ELSEIF (ACTIVITY EQ 1) = 9 ELSEIF (TRNCHKA EQ -9) = -8 Derived variables

Some other useful resources Question Bank –Linked to from ESDS –Contains searchable questionnaires for major surveys –Contains articles about major topics/concepts –Runs the survey link scheme – PEAS (Practical Exemplars on the Analysis of Surveys) –Contains learning materials on the impact of survey design on analysis (e.g. weighting and complex sample designs) –Uses the government surveys as exemplars – ONS website contains published reports, methodology etc. –

To find out more about other sources… Census data: Economic and Social Data Service has 3 other specialist services –Longitudinal –International –Qualidata –Plus core function for other datasets held at the UK Data Archive

Accessing the data Need to be registered with ESDS –Same system as the Census Registration System Easiest and free for academic users –Register online using your ATHENS username and password –Simple online form, takes about 10 minutes –No charge to download via the web Paper form can be used for teaching –Lecturer takes responsibility for the class –Students simply fill their details in on a paper form –Return form to the UK Data Archive Non-academic users –Will need to apply for an Athens account first –£500 Charge for commercial use per study

The licence This is not public data! We need to know who you are, how to contact you and what you are using the data for Agree not to attempt to identify individuals Only use the data for your stated purpose (you can re-register if you want to use the data for another use) Do not pass the data to unregistered parties (that includes deleting the data before passing on PCs!) Tell us if you publish using the data Some more sensitive or detailed datasets require more stringent licensing procedures –Special conditions: British Crime Survey –Special licence: Annual Population Survey

Obtaining data once registered Choice of downloading entire files: –SPSS, Stata, tab delimited formats for most files –Comes zipped up with documentation Or explore the data and download subsets in Nesstar (c. 200 files in this format – including most of the Government surveys) –Allows you to explore metadata without being registered –Can do basic exploratory anlyses (including OLS) online without downloading files –Can define subsets to download in a wider range of formats including SAS

Good practice: Some pointers Irresponsible use can threaten future access Keep data secure You wont understand the data unless you consult the documentation! Consider the impact of the sample design –Sample data has sample error; small cell counts are likely to be unreliable –Will the sampling design affect the standard errors? –Does weighting need to be applied to avoid bias Getting started guides, stats guides and topic guides are available on the ESDS site if you dont know where to start Contact helpdesk if you have any problems or find errors in the data User groups and news lists can help keep you informed

The last word: ESDS Helpdesk –(0161) (09:00-17:00)