Transcript UNFPA/UNECE/NIDI Training programme on international migration, Geneva, 24-28/01/2005 Analytical Measures and Methods George Groenewold, NiDi 1. 2. 3. Demographic Balance Equation: Method related concepts and definitions Main approaches: A.

UNFPA/UNECE/NIDI Training programme on international migration, Geneva, 24-28/01/2005
Analytical Measures and Methods
George Groenewold, NiDi
1.
2.
3.
Demographic Balance Equation:
Method related concepts and definitions
Main approaches:
A. Migration status is known: direct methods
A.1
Cross-tabulation migration status characteristics and an
example
B. Migration status is unknown: indirect methods
B.1
Vital Statistics or Residual Method and an example
B.2
Intercensal Cohort Component Method and an example
1. The Demographic Balance Equation
P(t+1)= P(t)+Births-Deaths+(Immigrants-Emigrants), or,
P(t+1)= P(t)+Natural Increase+Net Migration
2. Method related concepts and definitions
Out-migration (emigration) rate: number of persons that moved out of
place X divided by the average number of persons that were exposed to
migration
In-migration (immigration) rate: number of persons that live in place x, but
originated from elsewhere, divided by the average number of persons that
were exposed to migration
Net migration: the difference between the number of immigrants (or inmigrants) and the number of emigrants (or out-migrants)
Note:
no concensus about which persons should be in the denominator in
the above measures (UN, 1970, pp40-42.), depends on research
question which one to choose
Lifetime migrant: someone who at the time of the census lives away from
his/her place of birth
Cohort A cohort is a group of individuals experiencing the same demographic
(vital) event. Birth cohort=persons born in the same year. Migration
cohort=persons who emigrated from country X in the same year.
Life table. A life-table summarizes the (age specific) mortality experience in a
population in a particular year or particular (intercensal) period. Separate life
tables are constructed for men and women. A full life-table can be derived from
a set of Age Specific Mortality Rates (ASMR’s). Two important products of the
life table are: (1) the life expectancy at birth and (2) age-specific survival ratio’s
Survival Ratio. Indicator for the probability of surviving of persons in a
particular age-group X to the next higher age-group X+5. Survival ratio’s are
used in cohort component projections of the population
Cohort Component Projection Method. Estimation method that builds on the
principle that the size and age-structure of the current population can be
predicted from an age distribution in the past if interperiod births, deaths and
net numbers of (international) migrants are known
3. Main approaches:
A. Migration status is known: direct method (D)
A.1 Cross-tabulation of migration status characteristics
• Place of Usual Residence (POR) by Place of Birth
-life time migration moves only, not time-specific
-severe underestimation migration moves (intermediate
destinations not recorded)
• POR by POR 1 or 5 years ago
Example
-focus on recent migration flows
-UN recommends 5 years ago
-recall problem with fixed reference date
• POR by Place of Previous Residence by Duration of Residence
-refined migration cohort analysis, and migration and development
analysis
- recall problem
Table 1. Place of (usual) residence at time of census by Place of
residence 1 year ago
Place
of
residence
one year
ago
2001
D.K.B
Maekel
S.K.B
Anseba
Gash-Barka
Debub
Total 2002 pop.
MIDPERIOD Population
outmigrants
outmigration rate (per 1000)
inmigrants
inmigration rate (per 1000)
net number of migrants
net migration rate (per 1000)
Province of usual residence at census night, 2002 (POR)
D.K.B
Maekel
S.K.B
Anseba Gash-Barka
170
9
3
3
9
8
1050
12
8
12
7
8
775
5
13
6
16
5
675
20
9
12
14
9
1080
10
8
8
4
8
210
1103
817
704
1142
Debub
6
22
30
24
15
1580
1677
Total
200
1112
838
746
1139
1618
5653
Table 1. (continued)
Place
of
residence
one year
ago
2001
D.K.B
Maekel
S.K.B
Anseba
Gash-Barka
Debub
Total 2002 pop.
MIDPERIOD Population
outmigrants
outmigration rate (per 1000)
inmigrants
inmigration rate (per 1000)
net number of migrants
net migration rate (per 1000)
Province of usual residence at census night, 2002 (POR)
D.K.B
Maekel
S.K.B
Anseba Gash-Barka
170
9
3
3
9
8
1050
12
8
12
7
8
775
5
13
6
16
5
675
20
9
12
14
9
1080
10
8
8
4
8
210
1103
817
704
1142
Debub
6
22
30
24
15
1580
1677
Total
200
1112
838
746
1139
1618
5653
205
30
1108
62
828
63
725
71
1141
59
1648
38
5653
323
40
53
42
29
62
97
323
10
-9
-21
-42
3
59
0
Table 1. (continued)
Place
of
residence
one year
ago
2001
D.K.B
Maekel
S.K.B
Anseba
Gash-Barka
Debub
Total 2002 pop.
MIDPERIOD Population
outmigrants
outmigration rate (per 1000)
inmigrants
inmigration rate (per 1000)
net number of migrants
net migration rate (per 1000)
Province of usual residence at census night, 2002 (POR)
D.K.B
Maekel
S.K.B
Anseba Gash-Barka
170
9
3
3
9
8
1050
12
8
12
7
8
775
5
13
6
16
5
675
20
9
12
14
9
1080
10
8
8
4
8
210
1103
817
704
1142
205
30
146
40
195
10
49
1108
62
56
53
48
-9
-8
828
63
76
42
51
-21
-25
725
71
98
29
40
-42
-58
1141
59
52
62
54
3
3
Debub
6
22
30
24
15
1580
1677
Total
200
1112
838
746
1139
1618
5653
1648
38
23
97
59
59
36
5653
323
57
323
57
0
0
Table 1. (continued)
Place
of
residence
one year
ago
2001
D.K.B
Maekel
S.K.B
Anseba
Gash-Barka
Debub
Total 2002 pop.
MIDPERIOD Population
outmigrants
outmigration rate (per 1000)
inmigrants
inmigration rate (per 1000)
net number of migrants
net migration rate (per 1000)
Province of usual residence at census night, 2002 (POR)
Anseba Gash-Barka
S.K.B
Maekel
D.K.B
9
3
3
9
170
12
8
12
1050
8
13
5
775
8
7
20
675
5
16
6
1080
9
14
12
9
8
4
8
8
10
1142
704
817
1103
210
Debub
6
22
30
24
15
1580
1677
Total
200
1112
838
746
1139
1618
5653
1141
59
52
62
54
3
3
1648
38
23
97
59
59
36
5653
323
57
323
57
0
0
Debub
-4
14
22
20
7
Total
-10
9
21
42
-3
-59
0
205
30
146
40
195
10
49
1108
62
56
53
48
-9
-8
828
63
76
42
51
-21
-25
725
71
98
29
40
-42
-58
Province-specific net numbers of migrants
Place
of
residence
1 year
ago
2001
D.K.B
Maekel
S.K.B
Anseba
Gash-Barka
Debub
net total migrants 2002
(POR)
Province of residence at census night, 2002 (POD)
Anseba Gash-Barka
S.K.B
Maekel
D.K.B
0
-3
-4
1
0
-8
4
-1
-1
0
-4
4
11
0
8
3
-11
1
0
0
-7
-20
-22
-14
4
3
-42
-21
-9
10
59
B. Migration status is unknown: indirect methods
B.1
Vital Statistics or Residual Method and an example
Demographic Balance Equation
P(t+1)= P(t)+Births-Deaths+(Immigrants-Emigrants), or,
P(t+1)= P(t)+Natural Increase+Net Migration
or,
Net Migration=P(t+1) - (P(t)+Natural Increase)
Indirect estimation:
Migration estimate derived as ‘residual’ from two subsequent
census populations and intercensal natural increase (=recorded
or estimated intercensal births-deaths)
Table 2. Derivation of net migration estimates if population figures at two
points in time are known and numbers of births and deaths are
known between these points in time
Net migration to European Union, 2000, (*1000)
Population
Natural
Population
1.1.2000
increase
+
Natural
Increase
EU-15
Belgium
Denmark
Germany
Greece
Spain
France
Ireland
Italy
Luxembourg
Netherlands
Austria
Portugal
Finland
Sweden
UnitedKingdom
(1)
(2)
376.455,2
10.239,1
5.330,0
82.163,5
10.542,8
39.441,7
59.225,7
3.776,6
57.679,9
435,7
15.864,0
8.102,6
9.997,6
5.171,3
8.861,4
59.623,4
(3)
372,4
10,9
9,0
-76,2
-2,0
27,2
240,6
23,1
-17,2
2,0
66,1
1,5
14,3
7,4
-3,0
68,7
Population Difference
1.1.2001
(5) -(4)
Net
Migration
Estimate
(4)
(5)
376.827,6
377.507,9
10.250,0
5.339,0
82.087,3
10.540,8
39.468,9
59.466,3
3.799,7
57.662,7
437,7
15.930,1
8.104,1
10.011,9
5.178,7
8.858,4
59.692,1
10.262,2
5.349,2
82.192,6
10.564,7
39.489,6
59.521,3
3.819,7
57.844,0
441,3
15.983,1
8.121,3
10.022,8
5.181,1
8.882,8
59.832,1
680,3
12,2
10,2
105,3
23,9
20,7
55,0
20,0
181,3
3,6
53,0
17,2
10,9
2,4
24,4
140,0
Source: Eurostat Statistics in Focus, Population and social conditions, Theme 3 - 7/2002
Table 2. (continued)
Net migration to European Union, 2000, (*1000)
Population Natural Population Population Difference
1.1.2000
increase
+
1.1.2001
(5) -(4)
Natural
Increase
Net
Migration
Estimate
EU-15
Belgium
Denmark
Germany
Greece
Spain
France
Ireland
Italy
Luxembourg
Netherlands
Austria
Portugal
Finland
Sweden
UnitedKingdom
(1)
(2)
(3)
(4)
(5)
376.455,2
372,4
376.827,6
377.507,9
10.239,1
5.330,0
82.163,5
10.542,8
39.441,7
59.225,7
3.776,6
57.679,9
435,7
15.864,0
8.102,6
9.997,6
5.171,3
8.861,4
59.623,4
10,9
9,0
-76,2
-2,0
27,2
240,6
23,1
-17,2
2,0
66,1
1,5
14,3
7,4
-3,0
68,7
10.250,0
5.339,0
82.087,3
10.540,8
39.468,9
59.466,3
3.799,7
57.662,7
437,7
15.930,1
8.104,1
10.011,9
5.178,7
8.858,4
59.692,1
10.262,2
5.349,2
82.192,6
10.564,7
39.489,6
59.521,3
3.819,7
57.844,0
441,3
15.983,1
8.121,3
10.022,8
5.181,1
8.882,8
59.832,1
Total
increase
(2)+(5)
680,3
(7)
1.052,7
12,2
10,2
105,3
23,9
20,7
55,0
20,0
181,3
3,6
53,0
17,2
10,9
2,4
24,4
140,0
23,1
19,2
29,1
21,9
47,9
295,6
43,1
164,1
5,6
119,1
18,7
25,2
9,8
21,4
208,7
Source: Eurostat Statistics in Focus, Population and social conditions, Theme 3 - 7/2002
Table 2. (continued)
Net migration to European Union, 2000, (*1000)
Population Natural Population Population Difference Total
Rate
Net
Total
1.1.2000 increase
+
1.1.2001
(5) -(4) increase
of
migration increase
Natural
Natural
Rate
%
Increase
Net
(2)+(5) Increase
%
Annual
Migration
%
Population
Estimate
Growth
Rate
(1)
(2)
(3)
(4)
(5)
(7)
(8)
(9)
(10)
EU-15
376.455,2
372,4 376.827,6 377.507,9
680,3 1.052,7
0,10
0,18
0,28
Belgium
Denmark
Germany
Greece
Spain
France
Ireland
Italy
Luxembourg
Netherlands
Austria
Portugal
Finland
Sweden
UnitedKingdom
10.239,1
5.330,0
82.163,5
10.542,8
39.441,7
59.225,7
3.776,6
57.679,9
435,7
15.864,0
8.102,6
9.997,6
5.171,3
8.861,4
59.623,4
10,9
9,0
-76,2
-2,0
27,2
240,6
23,1
-17,2
2,0
66,1
1,5
14,3
7,4
-3,0
68,7
10.250,0
5.339,0
82.087,3
10.540,8
39.468,9
59.466,3
3.799,7
57.662,7
437,7
15.930,1
8.104,1
10.011,9
5.178,7
8.858,4
59.692,1
10.262,2
5.349,2
82.192,6
10.564,7
39.489,6
59.521,3
3.819,7
57.844,0
441,3
15.983,1
8.121,3
10.022,8
5.181,1
8.882,8
59.832,1
12,2
10,2
105,3
23,9
20,7
55,0
20,0
181,3
3,6
53,0
17,2
10,9
2,4
24,4
140,0
23,1
19,2
29,1
21,9
47,9
295,6
43,1
164,1
5,6
119,1
18,7
25,2
9,8
21,4
208,7
Source: Eurostat Statistics in Focus, Population and social conditions, Theme 3 - 7/2002
0,11
0,17
-0,09
-0,02
0,07
0,41
0,61
-0,03
0,46
0,42
0,02
0,14
0,14
-0,03
0,12
0,12
0,19
0,13
0,23
0,05
0,09
0,52
0,31
0,82
0,33
0,21
0,11
0,05
0,27
0,23
0,23
0,36
0,04
0,21
0,12
0,50
1,14
0,28
1,29
0,75
0,23
0,25
0,19
0,24
0,35
B.2 Intercensal Cohort Component Method and an example
• Data needs
- Age distributions by sex of two consecutive censuses
- intercensal life-tables by sex
- Estimate of intercensal fertility (ASFR by sex, or ASFR and sex ratio
at birth
• The principle
1. Project age groups (0-75 years) in first census, in year t, to the date of
the second census using appropriate intercensal life tables for each 5year projection interval:
P(t,x) × S(x, x+5)=P(t+5,x+5), where x=age-group
2. Estimate births in 5-year projction interval and project number of
surviving births in each 5-year projection interval
3. Repeat (1. ) and (2.) for each five-year projection interval and substract
the projected population at the time of the second census from the
observed census population to obtain age specific and total net
migration estimate (=indirect or residual estimation)
Figure 1. Lexis-diagram, illustrating the principle of Cohort
Component Projections
Step 1: derivation/selection
of an
appropriate
life table
Re: model answers,
27 april
2000, GG
T a b l e 1 : E x ce rp t f ro m l i fe -t a b le f o r w o m e n i n c o u n t ry X , b as e d o n 1 9 9 1 C en s u s , a s s u m ed to
b e re p re s en t at i v e fo r t h e 1 9 9 1 - 1 9 9 6 p e ri o d .
AG E
0
1- 4
5- 9
10 -14
15 -19
20 -24
25 -29
30 -34
.
.
.
Et c.
.
.
.
.
70 +
M(X ,N)
.09 649
.01 027
.00 603
.00 340
.00 417
.00 513
.00 581
.00 645
Q(X ,N)
.09 056
.04 001
.02 970
.01 687
.02 066
.02 531
.02 866
.03 173
l( X)
D(X ,N) L(X ,N)
S(X ,N)
10 0000
9 056
9 3857
.8 961 A
9 0944
3 639
35 4231
.9 597 B
8 7305
2 593
43 0044
.9 766
8 4712
1 429
41 9989
.9 815
8 3283
1 721
41 2247
.9 770
8 1563
2 064
40 2773
.9 729
7 9498
2 278
39 1877
.9 698
7 7220
2 450
38 0053
.9 664
To be used in table 3, column 3, rows 4 to 7
.19 611
... ..
1 7067
17 067
8 7028
T( X)
5 4458 77
5 3520 20
49 9778 9
45 6774 5
41 4775 6
37 3550 9
33 3273 6
29 4086 0
E( X)
54.4 59
58.8 50
5 7.2 45
5 3.9 21
4 9.8 03
4 5.7 99
4 1.9 22
3 8.0 84
To be used in table 2, last row, column
last shaded cell
.8 580
8 7028
__ ____ ____ ____ ____ ____ ____ ____
A=
V A L U E G I V E N I S F O R S U R V IV O R S H I P O F 5 C O H O R T S O F B IR T H T O
A G E G R O U P 0 - 4 = L( 0 , 5) / 5 0 00 0 0
B=
V A L U E G I V E N I S F O R S ( 0 ,5 ) = L ( 5 ,5 ) /L ( 0 ,5 )
5 .09 9
Step 2: Estimation of Births and births surviving projection interval
Age group
Female
Female
Population Population
1991
1996
(1)
(2)
Women at Age-Specific
risk of child
Fertility
Estimated
bearing
Rates
Births
(1991-1996) (A.S.F.R.) (1991-1996)
(3)=((1)+(2)/2)
(4) 5 x ((3)x(4))
15-19
1388
1459
1424
20-24
1269
1327
1298
25-29
1112
1216
1164
30-34
911
1069
990
35-39
716
876
796
40-44
628
690
659
45-49
553
602
578
Total births
Proportion of female births (sexratio=1.05)
Total female births (1991-1996)
Average 5-year survival ratio of newborns (L(0,5)/500,000)
Expected deaths among female births (1991-1996)
Total surviving female births
0.044
0.172
0.158
0.098
0.045
0.017
0.003
313
1116
920
485
179
56
9
3078
0.4878
1501
0.8961
156
1345
Step 3:
Derivation of age-specific net-migration estimates, assuming
that second census is five-years later than first census
Population Survival
Age group Census 1991
Ratio
(1)
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+
Total
1469
1487
1498
1388
1269
1112
911
716
628
553
470
399
335
268
424
12927
(2)
0.9597
0.9766
0.9815
0.9770
0.9729
0.9698
0.9664
0.9660
0.9609
0.9629
0.9796
0.9373
0.8985
0.8323
0.5880
Projected Population
Population
Census
1996
1996
(1)*(2)
(counted)
(3)
1345
1410
1452
1470
1356
1235
1078
880
692
603
532
460
374
301
472
13662
(5)
1297
1412
1453
1459
1327
1216
1069
876
690
602
530
459
373
302
471
13536
Estimated
Net
Migrants
(5)-(4)
(6)
Surviving
intercensus
births
-48
2
1
-11
-29
-19
-9
-4
-2
-1
-2
-1
-1
1 (268 x 0.8323) +
-1 (424 x 0.5880)= 472
-126
•
If census is 10 years apart, add another projection interval, I.e. repeat
steps 2 and 3 to determine projected population 10 years later. Use
different fertility and/or mortality rates if appropriate
•
This approach may slightly over- or underestimate the above agespecific net migration numbers
•
Solution:
•
1.
Reverse survive the survivors observed in the second census to
the date of the first census and derive estimate of net number of
migrants from that projection.
2.
Average the forward and reverse-survived estimate of age-specific
net migration
For Cohort Component Projections, use software, e.g.:
- PEOPLE
-FiVFiV
- PAS
-LIPRO
- DemProj
- PDPM_PC
- MortPak-Lite
Suggested literature.
- UN , 1970. Manual VI. Methods of Measuring Internal Migration.
Population Studies, No. 47. ST/SOA/Series A/47. Department of
Economic and Social Affairs New York.
- UN, 1992. Preparing Migration Data for Subnational Population
Projections. ST/ESA/SER.A/127. Department of International
Economic and Social Affairs. New York.
- Zaba, B. 1985. Measurement of Emigration using Indirect
Techniques. Ordina Editors. Liege
- Shryock, H.S. and J.S. Siegel. 1976. The Methods and Materials of
Demography. Academic Press, London.