Transcript PPTX

Evaluation of Age and Sex
Distribution Data
United Nations Statistics Division
Evaluation method of
age and sex distribution data
 Basic graphical tools
 Graphical analysis
Focus of the
presentation
 Population pyramids
 Graphical cohort analysis
 Age and sex ratios
 Summary indices of error in age-sex data
 Whipple’s index
 Myers’ Blended Method
 The use of stable population theory
 Uses of consecutive censuses
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Importance of age-sex structures

Planning purposes – health services,
education programs, transportation, labour
supply

Social science, economist, gender studies

Studying population dynamics – fertility,
mortality, migration

Insight on quality of census enumeration

Having strong effect on other characteristics
of a population

Determined by fertility, mortality and
migration, and follows fairly recognizable
patterns
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
What to look for at the evaluation
 Possible data errors in the age-sex structure,
including
Age misreporting (age heaping and/or age
exaggeration)
Coverage errors – net underenumeration(by
age or sex)
 Significant discrepancies in age-sex structure
due to extraordinary events
High migration, war, famine, HIV/AIDS
epidemic etc.
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Approaches to collecting age
and its impact on quality
 Age - the interval of time between the date of birth
and the date of the census, expressed in completed
solar years
 Two approaches
 The date of birth (year, month and day) - more precise
information and is preferred
 Completed age (age at the individual’s last birthday) –
less accurate
 Misunderstanding: the last, the next or the nearest birthday?
 Rounding to nearest age ending in 0 or 5 (age heaping)
 Children under 1 - may be reported as 1 year of age
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Basic graphical methods
- Population Pyramid
 Basic procedure for assessing the quality of census data on age
and sex
 Displays the size of population enumerated in each age group
(or cohort) by sex
 The base of the pyramid is mainly determined by the level of
fertility in the population, while how fast it converges to peak is
determined by previous levels of mortality and fertility
 The levels of migration by age and sex also affect the shape of
the pyramid
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Population pyramid (1)
– high population growth
Tunisia, 1994
90+
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
-150000
1944 birth cohort smaller- WWII ?
Female
Male
Wide base indicates high fertility
-100000
-50000
0
50000
100000
150000
Population
Source: Tabulated using data from United Nations Demographic Yearbook
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Population pyramid (2)
– low population growth
Age
Population Pyramid, Italy 2010
“baby boom”
100 +
95
90
85
80
75
70
65
60
55
50
1940-45 birth cohorts small due to WWII
Female
Male
45
40
35
30
25
20
15
10
5
0
-600000
Flattening base indicates long-term low fertility
-400000
-200000
0
200000
400000
600000
Population
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Population pyramid (3)
- detecting errors
 Under enumeration of young
children (< age 2)
 Age misreporting errors (heaping)
among adults
 High fertility level
 Smaller population in 20-24 age
group – extraordinary events in
1950-55?
 Smaller males relative to females in
20 – 44 - labor out-migration?
Source: Tabulated using data from U.S. Census
Bureau, Evaluating Censuses of Population and
Housing
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Population pyramid (4)- detecting errors
Tunisia, 1966
90+
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
-100000
Age heaping
Tunisia, 1994
Female
Male
-50000
0
50000
100000
Population
Declining fertility
90+
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
-150000 -100000 -50000
Female
Male
0
50000
Population
100000 150000
Population pyramid (4)- detecting errors
Bahrain, 2011
United Arab Emirates, 2005
80 - 84
80 - 84
70 - 74
70 - 74
60 - 64
60 - 64
50 - 54
50 - 54
Female
40 - 44
Male
30 - 34
Female
40 - 44
Male
30 - 34
20 - 24
20 - 24
`10-14
`10-14
0-4
-150000
-100000
-50000
0
50000
100000
0-4
-600000 -400000 -200000
Labour in-migration
0
200000 400000
Population pyramid (5)
- line instead of bars
Age and sex structure, Bangladesh, 2001
3500000
3000000
Age and sex structure, Bangladesh, 2001
2500000
10000000
2000000
9000000
1500000
8000000
1000000
7000000
500000
6000000
5000000
Age
80 +
75
70
65
60
4000000
3000000
2000000
1000000
Age group
Male
Data source: Tabulated using data from United Nations Demographic Yearbook
Female
80 +
75-79
70-74
65 - 69
60 - 64
55 - 59
50 - 54
45 - 49
40 - 44
35 - 39
30 - 34
25 - 29
20 - 24
15 - 19
10 - 14
0
5-9
Female
0-4
Male
55
50
45
40
35
30
25
20
15
10
5
0
0
Basic graphical methods
- Graphical cohort analysis
 Tracking actual cohorts over multiple censuses
 The size of each cohort should decline over each census due to
mortality, with no significant international migration
 The age structure (the lines) for censuses should follow the
same pattern in the absence of census errors
 An important advantage - possible to evaluate the effects of
extraordinary events and other distorting factors by following
actual cohorts over time
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Graphical cohort analysis – Example (1)
ALGERIA
1998
Age group
0-4
`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
Male
1627670
1820858
1918833
1782614
1472255
1259989
1056110
841768
691275
565289
371843
345318
301247
252003
163292
107732
2008
Age Group
0-4
`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
Male
1750097
1475674
1662260
1847311
1895704
1730409
1379085
1167249
1007683
817004
682357
547181
354694
314958
248672
181478
Birth cohort
2003-2008
1998-2003
1993-1998
1988-1993
1983-1988
1978-1983
1973-1978
1968-1973
1963-1968
1958-1963
1953-1958
1948-1953
1943-1948
1938-1943
1933-1938
1928-1933
1923-1928
1918-1923
 Data is organized by
birth cohort
 Exclude open-ended age
category
 People who were born in
the same years are
compared in the analysis
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Graphical cohort analysis – Example (1)
Algeria, 1998 and 2008 Censuses
Females
Male-1998
Male-2008
Female-1998
1928-1933
1933-1938
1938-1943
1943-1948
1948-1953
1953-1958
1958-1963
1963-1968
1968-1973
1973-1978
1978-1983
1928-1933
1933-1938
1938-1943
1943-1948
1948-1953
1953-1958
1958-1963
1963-1968
0
1968-1973
0
1973-1978
500
1978-1983
500
1983-1988
1000
1988-1993
1000
1983-1988
1500
1988-1993
1500
2000
1993-1998
Thousands
2000
1993-1998
Thousands
Males
Female-2008
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Graphical cohort analysis – Example (2)
Graphical Cohort Analysis, Republic of Korea, Male
1991, 2001 and 2011 censuses
2500000
2000000
1500000
1000000
500000
20
07
-2
20 01
02 1
-2
19 00
97 6
-2
19 00
92 1
-1
19 99
87 6
-1
19 99
82 1
-1
19 98
77 6
-1
19 98
72 1
-1
19 97
67 6
-1
19 97
62 1
-1
19 96
57 6
-1
19 96
52 1
-1
19 95
47 6
-1
19 95
42 1
-1
19 94
37 6
-1
19 94
32 1
-1
19 93
27 6
-1
19 93
22 1
-1
19 92
17 6
-1
92
1
0
Birth cohort
1991 Male
2001 Male
2011 Male
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Graphical cohort analysis – Example (2)
Graphical Cohort Analysis, Republic of Korea, Female,
1991, 2001 and 2011 censuses
2500000
2000000
1500000
1000000
500000
20
07
20 20
02 1 1
19 20
97 0 6
19 -20
92 0 1
19 19
87 9 6
19 19
82 9 1
19 -19
77 8 6
19 19
72 8 1
19 19
67 7 6
19 -19
62 7 1
19 19
57 6 6
19 -19
52 6 1
19 19
47 5 6
19 19
42 5 1
19 -19
37 4 6
19 19
32 4 1
19 19
27 3 6
19 -19
22 3 1
19 19
17 2 6
19 19
12 2 1
-1
91
6
0
Birth cohort
1991 Female
2001 Female
2011 Female
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Age ratios (1)
 In the absence of sharp changes in fertility or mortality,
significant levels of migration or other distorting factors, the
enumerated size of a particular cohort should be approximately
equal to the average size of the immediately preceding and
following cohorts
 The age ratio for a particular cohort to the average of the counts
for the adjacent cohorts should be approximately equal to 1 (or
100 if multiplied by a constant of 100)
 Significant departures from this “expected” ratio indicate either
the presence of census error in the census enumeration or of
other factors
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Age ratios (2)
 Age ratio for the
age category x to
x+4
5ARx
=
2 * 5P x
5Px-n
+ 5Px+n
5ARx
= The age ratio for the age
group x to x+4
5Px =The enumerated
population in the age
category x to x+4
5Px-5 = The enumerated
population in the adjacent
lower age category
5Px+5 = The enumerated
population in the adjacent
higher age category
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Age ratios (3) – example –Yemen
2004 Census
1994 Census
1.8
1.8
1.6
1.6
1.4
1.4
1.2
1.2
1
1
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
0
0
2004 Male
2004 Female
1994 Male
1994 Female
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Age ratios (3) – example –Yemen
Population Pyramid, 1994
81
72
63
54
45
36
27
18
9
0
Age ratio-single year, 1994 Census
25
20
15
-400000
-200000
Female
Male
0
200000
400000
10
Age misreporting
increases with ages
5
0
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82
Male
Female
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Sex ratios (1) - calculation
Sex Ratio =
5Mx
/ 5Fx
5Mx = Number of males enumerated in a specific age
group
5Fx = Number of females enumerated in the same age
group
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Sex ratios (2) - example
Sex ratio, 2008 and 1998 Censuses, Algeria
1.10
1.05
1.00
0.95
0.90
0.85
In most
societies the
SRB is
slightly over
1.0
2008
1998
Considerable female
advantage in mortality
at older ages
0.80
0.75
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Sex ratios (1) – cohort analysis
Sex ratio, cohort analysis, Algeria
1.08
 Fluctuation due to
age misreporting –
different level for
males and
females?
 Two censuses
indicate an excess
of male
population at age
group 55-59
1.06
1.04
1.02
1.00
0.98
0.96
0.94
0.92
0.90
0.88
0.86
0-4
`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
2008
1998
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Sex ratios (3) – cohort analysis
Cohort analysis, sex ratio, China
1.4
1.2
Sex Ratio
1
1982
0.8
1990
0.6
2000
0.4
0.2
0
96
9
1
99
-1
9
86
9
1
99
-1
0
76
9
1
98
-1
0
66
9
1
97
-1
0
56
9
1
96
-1
0
46
9
1
95
-1
0
36
9
1
94
-1
0
26
9
1
93
-1
0
16
9
1
92
-1
0
06
9
1
91
-1
0
96
8
1
90
-1
0
Birth Cohort
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Summary indices - Whipple`s Index
 Developed to reflect preference for or avoidance of a
particular terminal digit or of each terminal digit
 Ranges between 100, representing no preference for “0”
or “5” and 500, indicating that only digits “0” and “5”
were reported in the census
 If heaping on terminal digits “0” and “5” is measured;
Index=
 (P
(1 / 5) ( P
25
23
 P30  ......  P55  P60 )
 P24  .......  P60  P61  P62 )
 100
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing
Censuses
Evaluation
of Census
Amman, 19 – 23 October 2014
Source: Shryock
and Siegel,
1976,and
Methods
and Materials
of Data,
Demography
Whipple`s Index (2)
If the heaping on terminal digit “0” is
measured;
Index=
P30  P40  P50  P60
 100
(1 / 10) ( P23  P24  .......  P60  P61  P62 )
 The choice of the range 23 to 62 is standard,
but largely arbitrary. In computing indexes of
heaping, ages during childhood and old age are
often excluded because they are more strongly
affected by other types of errors of reporting
than by preference for specific terminal digits
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Whipple`s Index (3)
 The index can be summarized through the following
categories:
Value of Whipple’s Index
•
Highly accurate data
<= 105
•
Fairly accurate data
105 – 109.9
•
Approximate data
110 – 124.9
• Rough data
125 – 174.9
• Very rough data
>= 175
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Whipple’s index around the world
•Many of the countries that continue to have high
Whipple’s Index values are in Sub-Saharan Africa
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Data source:
Demographic
Yearbook
issue
age 19
heaping:
Housing
Censuses and
Evaluationspecial
of Census
Data, on
Amman,
– 23 October 2014
http://unstats.un.org/unsd/demographic/products/dyb/dybcens.htm
Improvement in the accuracy of
age reporting over time
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Summary indices –
Myers` Blended Index
 It is conceptually similar to Whipple`s index, except that
the index considers preference (or avoidance) of age
ending in each of the digits 0 to 9 in deriving overall age
accuracy score
 The theoretical range of Myers` Index is from 0 to 90,
where 0 indicates no age heaping and 90 indicates the
extreme case where all recorded ages end in the same
digit
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Summary indices –
Myers` Blended Index
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Summary indices –
Myers` Blended Index
Age misreporting
Myers` Belended Index, Yemen, 1994 Census
30.00

25.00
20.00

15.00
10.00
5.00
Ages ending with 0
and 5 : overcounting
Ages ending with
other digits
(particularly with 1,
3, 6, 7 and 9) –
under counting
0.00
0
1
2
3
4
Male
5
6
7
8
9
Female
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Conclusion: Uses and limitations
 Assessment of the age and sex structure of the population
enumerated in a census is typically the first step taken in
evaluating a census by means of demographic methods
 Demographic methods provide:
 A quick and inexpensive indication of the general quality of
data
 Evidence on the specific segments of the population in which
the presence of error is likely
 “Historical” information which may be useful for interpreting
the results of evaluation studies based on other methods,
and in determining how the census data should be adjusted
for use in demographic analyses
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
Conclusion: Uses and limitations
 The major limitation of age and sex structure analysis is that it
is not possible to derive separate numerical estimates of the
magnitude of coverage and content error on the basis of such
analyses alone
 It is often possible to assess particular types of errors which are
likely to have affected the census counts for particular segments
of the population. Estimates of coverage error from other
sources often are required to verify these observations.
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014
References
• Shryock and Siegel, 1976, Methods and Materials of
Demography
• IUSSP Tools for Demographic Estimation
http://demographicestimation.iussp.org/
• PAS-Population Analysis Spreadsheets
http://www.census.gov/population/international/software
/uscbtoolsdownload.html
United Nations Workshop on Revision 3 of Principles and Recommendations for Population and
Housing Censuses and Evaluation of Census Data, Amman, 19 – 23 October 2014