Housekeeping Fire alarm: LOUD continuous ringing Turn right down corridor Down stairs Gather on...

Housekeeping

Fire alarm:LOUD continuous ringingTurn right down corridor

Down stairsGather on Oxford Road side of building

Men’s and Women’s toiletsTurn right, toilets at end of corridor

Using the hierarchy of the government surveys

Jo WathanCentre for Census and Survey Research

Economic and Social Data Service(Government Data)

ESDS Using Hierarchy: v.06/04 3

ESDS Government

• Part of the wider Economic and Social Data Service, ESRC funded data dissemination and support service.

• ESDS is headed by UK Data Archive, also involves MIMAS and CCSR at the University of Manchester and ISER at the University of Essex

• ESDS Government, headed by CCSR. • Supports the large scale, continuous, cross-

sectional surveys collected by ONS and NatCen• Data dissemination carried out by UKDA• Value added services and user support carried out

by CCSR


This afternoon…

• What is hierarchical data? • What is the research purpose of

hierarchical data?• What hierarchy is available in ESDS

Government datasets?• Working with hierarchy in SPSS and Stata• Practical exercise


What is hierarchy?

• Data which can be analysed at more than one level, where smaller levels are nested within higher levels

• Most commonly seen in the form of household data, where information is collected on all individuals within the household – Data contains a variable indicating which household

an individual lives in– Data can be analysed at the household level or the

individual level– Often possible to analyse at the family level too

• Other forms of hierarchy available, eg. Sub-individual level (e.g. information per hospital stay, per crime reported)


Compared with flat files…

• Contextual information may be present, e.g. individual asked about size of household but:– Information collected from only one level– Not usually appropriate to use data at other

levels– Not usually possible to create additional derived

variables at other levels– E.g. information collected from one individual

within household


Hierarchical data: conceptually

Household 1North West

Social rented

Household 2Wales

Owner occupier

Person 1HoH

Female28

GCSEP/T WorkNo LTILL

Person 2Son of HoH

Male12N/AN/A

No LTILL

Person 1 HoHMale33

DegreeF/T Employee

No LTILL

Person 2Spouse of HOH

Female31

DegreeP/T Employee

No LTILL

Person 3Parent of HoH

Female 72

No qualsEcon Inactive

LTILL


More complex hierarchy…

Household 1 Household 2

Family 1 Family 2 Family 3

hoh Son of hoh Hoh Wife of hoh Mother of hoh

In patient 1

In patient 2

In patient 1


What does the data look like?Flattened data (GHS)


What does the data look like (2)Multiple tables (FES)

Household.por

Jobmain.por


Use the hierarchy to…

• Better describe the household• Describe the household context of an

individual• Look at intra-household differences

(& sameness)


Describing the householde.g. Is the household deprived / in

poverty?• Equivalising income (e.g. FRS)

– Need information on total income (all members not just Household Reference Person)

– Need information on household composition

• Identifying workless households– E.g. Gregg and Wadsworth (1999)


Workless households (source FES, various years 1968-1996)

0

5

10

15

20

25

68 70 72 74 76 78 80 82 84 86 88 90 92 94 96

Year

Pe

rce

nta

ge

(o

f p

res

en

t w

ork

ing

ag

e h

oh

)

workless households

children in worklesshouseholds

Source: Richard Dickens, Paul Gregg and Jonathan Wadsworth(2000) ‘New Labour and the Labour Market, CMPO Working Paper Series00/19 Table 5


The effect of partnership on employment (mothers)

fig 5.8: Employment Activity by all mothers (of dependent children) aged 16-59 by Partnership 1975-1996

0

10

20

30

40

50

1975 1981 1991 1996

Year

Perc

enta

ge

Partnered, f/t

Partnered, p/t

Unpartnered, f/t

Unpartnered, p/t


Ethnic homogeneity -

% hhold members in same ethnic group as HOH

0 20 40 60 80 100

White

Black caribbean

Black-Other

Indian

Pakistani

Source 1991 Household SAR


Hierarchy in some key datasets

SurveyHhd hierarchy?

Levels Type

GHS Household,Family,Individual,Sub Individual

Flat file

LFS Household, Family,Individual

Flat files(QLFS/Hhd data)

FES Multiple, inc. household, person, family unit, benefit unit

Multiple files

FRS Household,Benefit Unit, Individual Multiple files

HSE Household, Individual(watch out for variable samples)

Flat files (1 all inds, 1 all resps)

BSAS Individual Flat file

BCS Individual,Incident (Hhd context only)

Multiple files

BHPS Household, Individual (& below) Multiple files

Household SARs

Household, Family, Individual Flat file


Main Levels

• Household – group who have the accommodation as their only or

main residence and who either share one meal a day or share the living accomodation.

– Useful for coresidence or policy related issues • Family Unit

– An individual plus partner plus any unmarried children– The census definition of family unit excludes single

childless individuals– Useful for identifying partnership and parenthood

relationships• Benefit Unit

– Adult children in separate unit from parents

– Useful when considering income and benefits• Check your definitions (despite harmonisation)


Identifying the units

• You will need a unique identifier for the unit at each level

• Several variables may be needed to be used in combination

• You may need to compute a unique identifier

• Will need to read the documentation to assess this


Straightforward: GHS 00-01

• To identify a household use HSERIAL• To identify an individual within the

household use PERSNO• To identify a family unit use FSERIAL• To identify a family unit within a household

use AFAM• To identify the household reference person

test for PERSNO = HRP (HRP gives the person no. for the HRP)

• Similarly to locate the Family Unit head test for FUH=PERSNO


Complex e.g. QLFS 2003• If interested in using household information use the

Household File• Information about identifiers is in the read file• Household identifier is Remserno – however this is

not present in all LFS datasets• To compute use:

– Week x 10000000 +– W1yr x 1000000 +– Qrtr x 100000 +– Add x 1000 +– Wafnd x 100 +– Hhd

• This has to be used together with either CASEID or QUOTA (which are identical) – could combine this with Remserno to derive an easier to use household ID

• To identify a person in the household use person


Working with hierarchical data

• Which level should I analyse at?• Manipulating data in SPSS

– Menu driven approach– Syntax

• Manipulating data in Stata


Which level should I analyse at?

Hhd ID

Personnumber

Relationship to HRP

family

Income p/w

age tenure health

Relation-ship to FUH

FUH

Hid Person Reltohrp Fam Inc Age Tenure Health

Reltofuh fuh

1 1 self 1 dna 63 Soc rent Poor Self yes

2 1 self 1 300 21 Priv rent Good Self Yes

2 2 none 2 400 28 Priv rent Good Self Yes

2 3 none 3 100 19 Priv rent Ok Self Yes

3 1 self 1 700 43 Own occ Good Self Yes

3 2 partner 1 500 40 Own occ Good Partner No

3 3 child 1 N/a 12 Own occ Good Child No

4 1 self 1 200 35 Own occ Good Self Yes

4 2 partner 1 90 34 Own occ Ok Partner No

5 1 self 1 450 25 Soc rent Ok Self Yes

5 2 child 1 N/a 4 Soc rent Poor Child No

5 3 child 1 N/a 2 Soc rent ok child no


Understanding the data

• What is the default case/unit of analysis in the dataset?

• How many cases are in the data?• How many households are in the data?• How many family units are in the data?• How many households have more than

one family unit? • How large is the largest household?• How many lone families are in the data?


Using the data

• What unit of analysis would you use to answer the following questions?

• Would you need create variables at different levels of analysis to answer the question?– What is the mean income per adult?– What proportion of children live with 2 parents?– What is the mean income per adult-equivalent

household member (where children count as half a household member)?

– Does your partner’s health affect your own?– How is total household income related to tenure?


Working with hierarchy in SPSS

• SPSS is not good at data manipulation!• To generate a household variable from

individual data need to use the aggregate command.

• Aggregate command creates a household level file, with:– 1 case per household– Contains the household ID variable specified plus

any aggregate variables defined

• Slow, memory intensive, unnecessarily complicated compared with some other packages…


Creating a summary variable at the household level adding the number of people in the household

Rectangular file Aggregate file –household level

HH 1 Person 1 person 2 person 3 person 4 HH 2 person1 person 2

Nperhh HH1 4 HH2 2


Step1: Creating a summary variable at the household level Finding the oldest person in the household


HH 1 Age Person 1 56 person 2 44 person 3 13 person 4 6 HH 2 person1 22 person 2 25

Oldest HH1 56 HH2 25


Creating a summary variable at the household level Identifying the health of the Household Reference Person


ReltoHRP health HH1 self poor spouse ok child good child good HH 2 self good none good

hrphlth HH1 poor HH2 good


Aggregation at the household level

• You can work at the level of the household– Use the aggregate outfile– Remember to carry across other household level

variables that you will need into the aggregate file as part of the aggregate procedure

• Or match the household level variable back to the original individual level dataset…


Aggregate and match back to individual file

• Usually it is best to match back your aggregated variable to the master file– the household variable is distributed to each

individual– you can then select on household head, family

head to work at level of household or family– Or you can link information about the household

to the individual


Match the aggregate variables back to each individual in the household Rectangular file Aggregate file –household level

HH 1 Nperhh Oldest Person 1 4 44 person 2 4 44 person 3 4 44 person 4 4 44 HH 2 person1 2 76 person 2 2 76

Nperhh Oldest HH1 4 44 HH2 2 76


SPSS syntax used*compute a variable which is a low value, but which takes the (higher) value for health when

respondent is hrp.

compute hlthrep = -9.if (reltohrp = 1) hlthrep = health.crosstabs hlthrep by health by reltohrp.sort cases hid.aggregate outfile = "c:\work\esds\aggfile.sav"

/break hid/nperhh = n(hid)/oldest = max(age)/hrphlth = max(hlthrep).

execute.

match files/file = */table = "c:\work\esds\aggfile.sav"/by hid.

execute.


Working with hierarchy in Stata

• Stata much better at data manipulation than SPSS

• Not necessary to create an additional file• Simply run the appropriate procedure for

each household separately– Sort the data by the household identifier first– Use the by household identifier subcommand


The equivalent Stata commands:

sort hidegen nperhh = count(hid), by (hid)egen oldest = max(age), by (hid)gen hlthrep = -9replace hlthrep=health if (reltohrp == 1)egen hrphlth = max(hlthrep), by (hid)


Some issues…• Is the data representative for your choice

of unit?– Looking at individuals in a household survey will

generally omit individuals not living in households

– Weighting may be necessary to counteract survey design

– If the survey was not designed to analyse using the units you use, will it still be representative?

• Will there be any clustering effects?– Individuals within households will be more alike

than individuals in general– This could affect the accuracy of the estimates

Housekeeping Fire alarm: LOUD continuous ringing Turn right down corridor Down stairs Gather on...

Documents

Transcript of Housekeeping Fire alarm: LOUD continuous ringing Turn right down corridor Down stairs Gather on...