Life expectancy by NS-SEC
Structure, technical and conceptual issues and results
BSPS 8 Sept 2011
Brian Johnson
ONS
Health & Life Events Division
Newport
Brian.johnson@ons.gsi.gov.uk
Introduction
• Why life expectancy by NS-SEC?
• What is NS-SEC and how is it derived?
• Why is the ONS Longitudinal Study vital to
this analysis?
• Main technical problems and approach to
them
• Conceptual concerns
• Summary results
Background
• ONS has produced life expectancy by
Registrar General’s social class (RGSC) for
the period 1972-2005
• In 2001 RGSC was replaced by NS-SEC for
official statistics
• Need to produce life expectancy by NS-SEC
• This is how it was done
Registrar General’s social class
Non-manual
I
Professional
II Managerial and technical
IIIN Non-manual skilled
Manual
IIIM Manual skilled
IV Manual semi-skilled
V Manual unskilled
Life expectancy at birth by social class, for male &
females, England and Wales, 1972-2005. Nonmanual vs Manual
Males
Years
Females
Years
80
85
75
80
70
75
Non-manual
Non-manual
Manual
Manual
65
70
1972-76
1977-81
1982-86
1987-91
1992-96
1997-2001
2002-2005
Source: ONS Longitudinal study
1972-76
1977-81
1982-86
1987-91
1992-96
1997-2001
2002-2005
What is NS-SEC?
• Socio-economic classification based on
occupation
• Conceptually based on ‘employment
relations’
• Job security/prospects/autonomy
• ‘service contract’ relationship
• ‘labour contract’ relationship
NS-SEC operational and analytical
categories
Operational categories
Seven-class
L1
Five-class
Three-class
1 Professional and
managerial
occupations
1 Professional and
managerial
occupations
1 Employers in large establishments
L2
L3
2 Higher managerial occupations
3-6 Higher professional occupations
L4
L5
7-10 Lower professional and higher
technical occupations
11 Lower managerial occupations
L6
L7
12 Higher supervisory occupations
13-16 Intermediate occupations
L8
L9
L10
L11
L12
17-18
19-20
21
22-23
24-30
L13
31-35 Routine occupations
Employers in small establishments
Own account workers
Lower supervisory occupations
Lower technical occupations
Semi-routine occupations
1 Higher managerial
and professional
occupations
2 Lower managerial and
professional
occupations
3 Intermediate
occupations
4 Small employers and
own account workers
5 Lower supervisory
and technical
6 Semi-routine
occupations
7 Routine occupations
Source: Rose D and Pevalin D (ed) (2003) A Researcher’s Guide to the
National Statistics Socio-economic Classification.
2 Intermediate
2 Intermediate
occupations
3 Small employers occupations
and own account
4 Lower supervisory
and technical
3 Routine and
5 Semi-routine and manual occupations
routine occupations
Part of NS-SEC derivation matrix
Standard Occupational Classification 2000
1111
1112
1113
1114
1121
1122
1123
1131
1132
Senior officials in national gov't
Directors of major organisations
Senior officials in local gov't
Senior officials of other organisations
Production and works managers
Managers in construction
Managers in mining and energy
Financial managers & chartered secs
Marketing and sales managers
Employer
1.1
1.1
4
4
4
4
4
1.2
4
Selfmanag
employed
er
1.1
1.1
4
4
4
4
4
1.2
4
1.1
1.1
1.1
2
1.1
2
1.1
1.1
1.1
supervisor
employee
1.1
1.1
1.1
2
1.1
2
1.1
1.1
1.1
1.1
1.1
1.1
2
1.1
2
1.1
1.1
1.1
1.1
Employers in large organisations and higher managers
1.2
Higher professional occupations
4
Self-employed and own account workers
2
Lower managerial and professional occupations
Source: ONS (2002): The NS-SEC User Manual
Life Table (illustrative)
<1
1-4
5-9
10-14
15-19
20-24
25-29
30-34
35-39
40-44
45-49
50-54
55-59
60-64
65-69
70-74
75-79
80-85
85+
x
n
0
1
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
1
4
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
11
ax
0.1
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
pop
2,533
11,130
15,519
16,409
16,133
21,482
15,997
16,026
19,800
16,076
13,404
13,027
10,051
10,220
9,190
7,427
5,231
2,884
1,840
death
20
1
2
4
9
10
22
35
34
39
59
108
136
176
320
445
414
355
347
Mx
0.007896
0.000090
0.000129
0.000244
0.000558
0.000466
0.001375
0.002184
0.001717
0.002426
0.004402
0.008290
0.013531
0.017221
0.034820
0.059917
0.079144
0.123093
0.188587
qx
0.0078401
0.0003593
0.0006442
0.0012181
0.0027854
0.0023248
0.0068527
0.0108605
0.0085492
0.0120568
0.0217688
0.0406107
0.0654412
0.0825516
0.1601602
0.2605539
0.3303543
0.4706350
1.0000000
px
0.992160
0.999641
0.999356
0.998782
0.997215
0.997675
0.993147
0.989140
0.991451
0.987943
0.978231
0.959389
0.934559
0.917448
0.839840
0.739446
0.669646
0.529365
0.000000
lx
100000
99216
99180
99116
98996
98720
98490
97816
96753
95926
94770
92706
88942
83121
76259
64046
47358
31713
16788
dx
784
36
64
121
276
230
675
1062
827
1157
2063
3765
5820
6862
12214
16687
15645
14925
16788
Lx
99294
396793
495742
495280
494289
493026
490765
486422
481698
476739
468690
454120
430157
398451
350763
278510
197679
121253
89019
Tx
7198691
7099397
6702604
6206862
5711582
5217293
4724267
4233501
3747080
3265381
2788642
2319953
1865832
1435675
1037224
686461
407951
210272
89019
ex
71.99
71.55
67.58
62.62
57.70
52.85
47.97
43.28
38.73
34.04
29.43
25.02
20.98
17.27
13.60
10.72
8.61
6.63
5.30
Period and Cohort Life expectancy
• Period life expectancy (shown here) reflects mortality
rates prevailing at all ages during calendar period to
which it refers
• Therefore ‘life expectancy at birth’ for child born in
2004 is the number of years that child could expect to
live if age-specific mortality rates stayed as in 2004
• Cohort life expectancy allows for anticipated future
changes in mortality rates – projection implies
element of subjectivity
LS Structure
Entries 1971-2008
New Births
272,000
Immigrations
174,000
Exits 1971-2008
Deaths
239,000
Embarkations 40,000
1971
1981
1991
2001
Original
sample:
530,000
members;
selected from
1971 Census
534,000
sample
members
found at 1981
Census
543,000
sample
members
found at 1991
Census
540,000
sample
members
found at 2001
Census
Events:
1971-2008
Births to sample women 260,000
Births to sample men
49,500
Infant Deaths
2,200
Widow(er)hoods
82,000
Cancer registrations
114,000
What can the LS offer the study of life
expectancy by social classification?
• Based on census returns and administrative
sources – low levels of ‘attrition’ (compared
with survey data)
• Can attribute social indicator (eg. social
class/occupation) several years before death
– no need to rely on death registration
• Eliminates numerator-denominator bias - uses
actual person-years at risk as denominator
Hierarchy for assignment of socioeconomic class
Present at a census 81-01
Present 81
own
spouse's
father's
mother's
Present 91
own
spouse's
father's
mother's
father's at birth 1981-91, mother's at birth 1981-91
Present 01
own
spouse's
father's
mother's
father's at birth post 1991-2001, mother's at birth 1991-2001
Not present at a census
father's at birth
mother's at birth
Person-years at risk
AGE
Calendar
Year
1971
1972
60
61
62
63
64
Census 1971
5
B
/////////////// 3
9
B
/////////////// 3
Year
1973
9
B
/////////////// 3
1971
4
1974
D
1972
1973
Period at risk in younger age-group in each calendar year
/////////////// Period at risk in older age-group in each calendar year
Source: Fox AJ & Goldblatt PO Series LS No 1 OPCS
1974
Age
group
60
61
61
62
62
63
63
PYRs
5 months
3 months
9 months
3 months
9 months
3 months
4 months
Structure of Life Expectancy by NS-SEC project
Members’
Occupation/emp
status at
census
81,91,01
Non-members’
Occupation/emp
status at
census
81,91,01
New births
80’s,90’s,00’s
Father/mother
Occ/emp status
NSSEC M
D
E
R
I
V
A
T
I
O
N
A
T
R
I
C
E
S
Cancelled
Ciphers
Own
NS-SEC
Losses to
Follow up
Father’s
Mother’s
Spouse’s
NS-SEC
81
91
01
NS-SEC80
Derivation
Matrix project
Father’s
Mother’s
NS-SEC
At birth
NS-SEC
Classifica
-tion
program
Deaths &
Pyrs
program
Age-specific
mortality
rates
Life
Tables
Components of the project
1.
2.
3.
4.
5.
6.
Construct “NS-SEC80” derivation matrix using 1981
occupational classification and employment status to produce
(reduced) NS-SEC classification for 1981 Census
Construct ‘own’ NS-SEC at each census where present
Construct father’s, mother’s and spouse’s NS-SEC at 1981,
1991 & 2001 censuses where present, using LS non-members
file
Construct father’s and mother’s NS-SEC for 1980’s, 1990,s
and 2000’s new births
Construct hierarchical scheme for assigning ‘sec’ to each LS
member, using own or father’s, mother’s, or spouse’s class
Adapt rule-based programs to obtain age-specific mortality
rates by NS-SEC
NS-SEC90 analytic classes– using
SOC90
soc90
STANDARD OCCUPATIONAL CLASSIFICATION 1990 OCCUPATION
EmpSelf-emp
UNIT GROUP
Manager
TITLE
loyer
100
101
102
103
110
111
112
113
120
no
employees
General administrators; national government
1.1
1.1
1.1
General managers; large companies and organisations
1.1
1.1
1.1
Local government officers
4
4
1.1
General administrators; national government (HEO 2to Senior Principal)
2
2
Production, works and maintenance managers
4
4
1.1
Managers in building and contracting
4
4
2
Clerks of works
4
4
2
Managers in mining and energy industries
4
4
1.1
Treasurers and company financial managers
1.2
1.2
1.1
Super
Employee
visor
1.1
1.1
1.1
2
2
2
2
1.1
1.1
1.1
1.1
1.1
2
1.1
2
2
1.1
1.1
Technical issues
• No one-to-one mapping of CO80 to SOC90
• There is a bridge coding which applies to
both 1981 and 1991
• But 1981 Census occupations not classified
by it!
Comparability of OPCS CO80 occupation codes
and SOC90 unit groups
SOC90
CO80
46%
16%
38%
Source: OPCS (1991) “Standard Occupational Classification”, Volume 3, HMSO
Solutions
• Map those occupations which have exact or
near-exact linkage
• Add other occupations which are not uniquely
linked but map to the same standard NS-SEC
analytic groups
• Use empirically based rules to estimate the
rest (approx 3% of population)
Part of NS-SEC80 derivation matrix
NS-SEC analytic classes
1981 occupation (CO80)
SOC90
coding
Judges, barristers, advocates, solicitors
240/241/242
Chartered and certified accountants
250
Cost and works accountants
251
Estimators
360
Valuers, claims assessors
360/1
Financial managers
120
Underwriters, brokers, investment analysts
361
Taxation experts
362
Personnel and industrial relations officers
124/363
O and M, work study and OR officers
125/364
Economists, statisticians, actuaries
252
Systems analysts, computer programmers 126/214/320
Self
Self
manager superemployed employed
visor
with
without
emps
emps
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
2
2
2
2
2
2
1.2
2
1.2
1.2
1.1
1.1
2
2
1.2
2
1.2
1.2
1.2
1.2
2
2
1.1
2
1.2
1.2
1.1
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.1
1.2
employee
1.2
1.2
1.2
2
2
1.1
2
1.2
2
1.2
1.2
1.2
Validation – cross-tab of 1993 deaths
nssec_90
2
3
50
0
38
33
24,049
828
40 20,771
0
0
0
0
0
191
0
0
nssec80
1.1
1.2
2
3
4
5
6
7
1.1
4,823
4
216
0
0
0
0
0
1.2
20
6143
89
11
18
0
0
0
Total
5,043
6281
24,178
220
138
129
off diag
4
0
0
6
0
15,026
0
0
0
5
0
0
40
0
0
22,701
76
16
6
0
0
33
50
0
113
33,056
187
7
0
0
0
36
0
242
636
46,615
21,823
15,032
22,833
33,439
47,530 176,157
1052
6
132
383
914
4,893
6,218
25,261
20,908
15,044
23,056
33,959
46,818
2974
1.69%
Conceptual problem
• NS-SEC was designed for the economic
structure of 2000 not 1980
• May be criticised as conceptually invalid
• But empirically, it works!
Period life expectancy – males at birth
82
80
Higher managerial &
pro f
78
Lo wer managerial &
pro f
76
Intermediate
74
Small emplo yers
72
Lo wer superviso ry &
tech
70
Semi-ro utine
68
66
Ro utine
64
1982-86
1987-91
1992-96
1997-2001
2002-06
Period life expectancy – females at
birth
86
Higher managerial
& prof
84
Lower managerial
& prof
Intermediate
82
80
Small employers
78
Lower supervisory
& tech
76
Semi-routine
74
Routine
72
1982-86
1987-91
Source ONS Longitudinal Study
1992-96
1997-2001
2002-06
Period life expectancy – men aged 65
20
19
Higher managerial
& pro f
18
Lo wer managerial
& pro f
17
Intermediate
16
15
Small emplo yers
14
Lo wer superviso ry
& tech
13
Semi-ro utine
12
11
Ro utine
10
1982-86
Source ONS Longitudinal Study
1987-91
1992-96
1997-2001
2002-06
Period life expectancy – women aged 65
24
Higher managerial &
pro f
22
Lo wer managerial &
pro f
20
Intermediate
18
Small emplo yers
16
Lo wer superviso ry &
tech
14
Semi-ro utine
12
Ro utine
10
1982-86
1987-91
Source ONS Longitudinal Study
1992-96
1997-2001
2002-06
Summary
• ONS has a series of trends in life expectancy by (RG)
social class
• Has now developed a series by NS-SEC also using
the ONS Longitudinal Study (published Feb 2011*)
• Similar pattern of socio-economic gradient apparent
in results
*For full description of methods and context of results see Health Statistics Quarterly volume
49
http://www.ons.gov.uk/ons/rel/hsq/health-statistics-quarterly/trends-in-life-expectancy-by-thenational-statistics-socio-economic-classification-1982-2006/health-inequalities-in-the-21stcentury.pdf