1. Global Economy and Business MOBILITY AND MIGRATION
Prof.ssa Luisa Natale

2. MOBILITY AND MIGRATION
4a. MEASURES

3. Measures The study of migration focuses on:
Intensity (absolute values, rate, …)
Distance and direction of flow - that is, specifying the origin and destination of the migration flows
C) The structure of the migrant population according to the main features of biodemographic, socio-economic, ethnic and cultural type

4. A) Intensity of migration
Estimate of NET MIGRATION
Net total of migrants during the period, that is, the total number of immigrants less the annual number of emigrants, including both citizens and noncitizens

5. NET MIGRATION ESTIMATE
A. Direct estimate
For example:
Equation of Population: Italy 2010 (slide 6)
Source →//demo.istat.it/index.html
→ Bilancio demografico 2010
B. Indirect estimate

6. Total Population Balance
nPt = nPt-1+nB∆t - nD∆t +n I∆t - nE∆t
B = births
D = deaths
I = Immigration
E = Emigration
t = time, n = type of population (in this case, total population)
nB∆t - nD∆t = Natural Increase
n I∆t - nE∆t = Net Migration

7. Total Population Increase
nPt - nPt-1 = Total population increase
nPt - nPt-1= nB∆t - nD∆t +n I∆t - nE∆t
This is the classical definition of a population balance

8. The real population balance
In countries with census and population registers, the balance is not merely a result of natural and migration increase
Other components are present in a balance (see, for instance, Italy)

9. The two population balances
nPt - nPt-1= nB∆t - nD∆t +n I∆t - nE∆t
the classical population balance
nPt - nPt-1= nB∆t - nD∆t +n I∆t - nE∆t + n OI∆t - nOE∆t + n IntI∆t - nIntE∆t
n OI∆t - nOE∆t = other registered/cancelled
(n IntI∆t - nIntE∆t )= total internal balance
the real population balance (see Italy)

10. The internal migration balance
(n IntI∆t - nIntE∆t )= total internal balance = enrolled from others municipalities-cancelled to other municipalities It should be egual to zero, but due to late in the process of registration/deregistration of flows in each municipalities the balance is always different from zero (often fifty-sixty thousands of movements, very scarce in comparison of 1,3 millions of internal movements)

11. EXERCISE
Write:
1) the Equation of total population in Italy, 2010, (Direct estimate ,slide 12)
2) total population increase (Direct estimate, slide 12)

12. TOTAL POPULATION BALANCE A. Direct estimate (Italy, 2010)

13. EXERCISE Natural Increase= nB∆t - nD∆t = 561944 – 587488 = -25544
Net (International) Migration = Enrolled from abroad – cancelled to abroad = +n I∆t - nE∆t = – 78771= 380,085
Technical balance n OI∆t - nOE∆t = other registered – others cancelled = – =
(n IntI∆t - nIntE∆t )=total internal balance= =10949
Other components (net migration due to other reasons): – = - 68,427
Net Migration (other reasons compr.): – 68427= 311,658

14. Equation of Population: Italy 2010, 31.12
60,626,442 = 60,340,328 +(-25,544)+ 311,658
where:
Natural Increase: - 25,544
Net (International) Migration: ,085
Other components (net migration due to other reasons): - 68,427
Net Migration (other reasons compr.): + 311,658
Total Increase: 60,626, ,340,328 = 286,114

15. FOREIGN POPULATION BALANCE A. Direct estimate

16. Equation of Foreign population
Population Total Increase → fPt - fPt-1
fPt - fPt-1 = fBt - fDt + fIt - fEt - fNt +fOIt - fOEt +
+ fIntI∆t - nIntE∆t
B=births, D=deaths, I=Immigration, E=Emigration, N=Naturalization
O=technical adijustments, Int = internal moves; where:
fBt - fDt = Natural Increase
fIt - fEt = Net (International) Migration (enrolled from abroad-cancelled to abroad)
fOIt- fOEt =Technical balance (other enrolled-other cancelled)
fIntI∆t - nIntE∆t =Internal moves (enrolled from other municipalities - cancelled to others municipalities)

17. EXERCISE
Write:
1) the Equation of foreign population in Italy, 2010, (Direct estimate, slide 12)
2) foreign population increase (Direct estimate, slide 12)

18. Equation of Foreign population
fPt - fPt-1 = fBt - fDt + fIt - fEt - fNt +fOIt - fOEt +
+ fIntI∆t - nIntE∆t
B=births, D=deaths, I=Immigration, E=Emigration, N=Naturalization
O=technical adijustments, Int = internal moves; where:
fBt - fDt = Natural Increase = +72,958= 78, ,124
fIt - fEt = Net (International) Migration (enrolled from abroad-cancelled to abroad)= 424, ,817 =
fOIt- fOEt =Technical balance (other enrolled-other cancelled)= =
fIntI∆t - nIntE∆t =Internal moves (enrolled from other municipalities-cancelled to others municipalities) = – = 5377

19. FOREIGN NET MIGRATION ESTIMATE A. Direct estimate
Net (International) Migration:
Net Migration (other reasons compr.): – =

20. Equation of Foreign Population (Italy 2010)
4,570,317 = 4,235, , ,238 + (-65,938)
4,570, ,235,059 = + 72, , ,938
335,258 = 335,258
Total Increase = 335,258
Net Migration (other reasons compr.): +391,682 – 68, ,377 =
Natural Increase = +72,958
Naturalised = -65,938

21. Foreign population increase
(Italy 2010) =

22. EXERCISE Calculate the equation of the foreign population
by distinguish each component
Resident foreign population at 31 December and demographic balance from 9 October 2011 to 31 December Italy

23. Foreign contribution to the increase
During the 2010 (but the same happened in the previous years…) the total population increase in Italy could be disaggregated in two component:

24. NET MIGRATION ESTIMATE B. Indirect estimate
Estimation of net migration (nNMt)
by the availability of natural increase
(nBt - nDt) and population (type n)
in two points (nPt and nPt-1):
nNMt = nPt - nPt-1 – (nBt - nDt)

25. Example: Italy,
Population at 1 January 1992 = 56,773 Population at 1 January 2002 = 56,994 Total increase = Births ( ) = 5,416 Deaths ( ) = 5,592 Natural Increase = Net Migration = ?

26. Example: Italy,
Population at 1 January 1992 = 56,773 Population at 1 January 2002 = 56,994 Total increase = Births ( ) = 5,416 Deaths ( ) = 5,592 Natural Increase = Net Migration = 221 – (-176) = + 397

27. NET MIGRATION ESTIMATE B. Indirect estimate
Weakness
You can estimate only the balance (no information about gross flows)
in the case of a sub-national area you can estimate the internal balance + international balance
weakness of the measurement in developing countries

28. 1. Indirect estimate : Foreign Born Population
Case study
Population balance equation
bPt = bPt-1 - bDt + bIt - bEt
then:
bNM = bIt - bEt = bPt - bPt-1 + bDt
“Reduced Equation” (… births are lacking!)

29. 2. Indirect estimate: Foreign Citizen Population
Population equation
fPt = fPt-1 + fBt - fDt + fIt - fEt - fNt
Then: fNM = fIt - fEt = fPt – fPt- - fBt + fDt + fNt

30. MIGRATION INTENSITY OF INFLOW AND OUTFLOW
1. Interested to both the migratory flows → in and out flow, gross flow and net flow
2. Standardisation by population consistency, age, sex … → gross rate, specific rate

31. Migratory flows → in and out flow, gross flow and net flow
Considers as (Boyle, Halfacree, Robinson, 1998)
IMi = Gross In-Migration, the volume of in-migration moving into a place i
OMi = Gross Out-Migration, the volume of out-migration moving from a place i
In this case Net Migration is defined as the algebraic sum of gross flows:
NMi = IMi - OMi (as in the previous slides…)

36. Standardisation by population consistency, age, sex … → gross rate, specific rate
To allow comparison among different places or the same place over time the measures are standardized by dividing the volumes by the average population of the place, so obtaining a RATE

37. RATES IMRi = IMi / Pi x 1,000 that is in-migration rate
OMRi = OMi / Pi x 1, out-migration rate
NMRi = (IMi - OMi) / Pi x 1,000 net-migration rate
with Pi average population, that is the population on average counted during all the year (or during all the period)

38. Average population
A good approximation of this average population can be obtained:
a) using the population observed at the mid-term
b) using a semi-sum of the population at the initial and the final period considered.
Noting that in the case in which the observation of flows is made across a non-year period (for example, more than one year) the calculus must take into account this odd temporal reference.

39. The crude migration rate: an example
Total Population (Italy, 2010)
Foreign Population (Italy, 2010)
1 January
31 December
Average (1)
Immigration (2)
458856
424499
Emigration (3)
78771
32817
Net Migration (4)
380085
391682
Immigration Rate (2)/(1)
7,6
96,4
Emigration Rate (3)/(1)
1,3
7,5
Net Migration Rate (4)/(1)
6,3
89,0

40. Crude Net Migration Rate by Region - 2011 (per 1. 000 resident)
Crude Net Migration Rate by Region (per resident). Centre-North Regions
Region
Internal
External
Other causes
Total
Piemonte
1,0
6,6
-1,4
6,2
Valle d'Aosta
1,7
5,3
-1,2
5,8
Lombardia
1,5
-1,5
Trentino-Alto Adige
2,3
5,4
-0,9
6,8
Bolzano-Bozen
1,9
4,8
-0,7
6,0
Trento
2,7
-1,1
7,6
Veneto
0,4
6,7
-1,9
5,2
Friuli-Venezia Giulia
1,3
5,0
Liguria
1,8
-1,8
Emilia-Romagna
2,0
7,7
Toscana
1,4
7,1
-1,7
Umbria
0,6
7,9
-1,3
7,2
Marche
Lazio
1,6
7,3
-1,0

41. Crude Net Migration Rate by Region - 2011 (per 1. 000 resident)
Crude Net Migration Rate by Region (per resident). South Regions
Region Internal External Other Total
cause
_____________________________________________
Abruzzo 0,9 5,4 - 1,0 5,3
Molise 0,8 3,1 - 0,3 3,6
Campania - 3,7 2,5 - 0,3 - 1,5
Puglia - 2,1 1,9 - 0,4 - 0,6
Basilicata - 2,7 2,2 - 0,1 - 0,6
Calabria - 3,5 3,4 - 0,3 - 0,4
Sicilia - 1,7 2,3 - 0,6 0,0
Sardegna - 0,2 1,9 0,0 1,7
ITALIA * 5,3 - 1,1 4,3
Nord 1,3 6,6 - 1,6 6,3
Nord-ovest 1,4 6,5 - 1,5 6,4
Nord-est 1,3 6,8 - 1,8 6,3
Centro 1,3 7,2 - 1,3 7,2
Mezzogiorno - 2,2 2,5 - 0,4 - 0,1
Sud - 2,6 2,7 - 0,4 - 0,3
Isole - 1,4 2,2 - 0,4 0,4

42. Example
Calculate a immigration pluri-annual rate (IMR), considering:
nP =56,000,000 nP =55,000,000
IM = 900,000

43. Example: solution
nP =56,000,000 nP =55,000,000 IM = 900,000 Average Population ( ) = AP AP = (56,000,000+55,000,000)/2 * 2 = 111,000,000 Finally: IMR = 900,000 / 111,000,000 = 8,11 per thousands

44. Emigration and immigration rate: a paradox
The meaning of the out and in-migration rate unfortunately is not the same. While OMR is clearly a measure of propensity to go out of a population, IMR has not the same interpretation, because the propensity to enter to a specific place i moving from j different places depends of the propensity of these j different places to generate flows towards i. Clearly OMR is a measure of propensity (in other words it is a proxy of a probability), IMR is a measure of impact.

45. SPECIFIC RATES
IMRi,x = IMi,x / Pi,x per 1,000 that is in-migration age-specific rate
OMRi,x = OMi,x / Pi,x per 1,000 out-migration age-specific rate
NMRi,x = (IMi,x - OMi,x) / Pi,x per 1,000 net-migration age-specific rate
with Pi,x average population at age x, that is the yearly population in age x on average

46. Specific Rate: an Example. Outflows (abs. value and rate)
Specific Rate: an Example. Outflows (abs. value and rate). Male population, Italy 1991
age x
Px,t
Px,t+1
Average
Outflows
Outflow Specific Rate
Population
OAx,t (Abr.)
OIx,t (Interreg.
OARx,t
OIRx,t
292425
279983
286204
237
1072 1
286125
281773
283949
522
2839 2
287855
283370
285612,5
471
2643 3
280235
285289
282762
420
2406 4
281488
278884
280186
407
2034 5
291416
280661
286038,5
429
1779 6
295628
290391
293009,5
409
1855 7
303494
294793
299143,5
423
1542 8
312392
302720
307556
393
1490 9
319078
311715
315396,5
436
1465 10
324159
319253
321706
371
1303 11
336157
324123
330140
467
1689 12
358577
336069
347323
1254 13
372766
358533
365649,5
1219 14
393400
372696
383048
378
1323 15
416737
393242
404989,5
1340 16
437236
416509
426872,5
438
1442

47. Specific Rate: an Example. Outflows (abs. value and rate)
Specific Rate: an Example. Outflows (abs. value and rate). Male population, Italy 1991
age x
Px,t
Px,t+1
Average
Outflows
Outflow Specific Rate
Population
OAx,t (Abr.)
OIx,t (Interreg.
OEAx,t
OEIx,t
292425
279983
286204
237
1072
0,8
3,7 1
286125
281773
283949
522
2839
1,8
10,0 2
287855
283370
285612,5
471
2643
1,6
9,3 3
280235
285289
282762
420
2406
1,5
8,5 4
281488
278884
280186
407
2034
7,3 5
291416
280661
286038,5
429
1779
6,2 6
295628
290391
293009,5
409
1855
1,4
6,3 7
303494
294793
299143,5
423
1542
5,2 8
312392
302720
307556
393
1490
1,3
4,8 9
319078
311715
315396,5
436
1465
4,6 10
324159
319253
321706
371
1303
1,2
4,1 11
336157
324123
330140
467
1689
5,1 12
358577
336069
347323
1254
1,1
3,6 13
372766
358533
365649,5
1219
3,3 14
393400
372696
383048
378
1323
1,0
3,5 15
416737
393242
404989,5
1340
0,9 16
437236
416509
426872,5
438
1442
3,4

48. Male outflows rate (interregional and external) by age. Italy, 2010.

49. Male outflows rate (interregional and external) by age. Italy, 2010.
The age-model of OEF and OEI is quite the same

50. Total Mobility Rate: an example
age x
Px,t
Px,t+1
Aver.
Outflows
Outflow Specific Rate
Pop.
CFx,t
CIx,t
OEFx,t
OEIx,t
292425
279983
286204
237
1072
0,8
3,7 1
286125
281773
283949
522
2839
1,8
10,0 2
287855
283370
285612,5
471
2643
1,6
9,3 3
280235
285289
282762
420
2406
1,5
8,5 4
281488
278884
280186
407
2034
7,3 … 79
124564
137066
130815 45
340
0,3
2,6
80 +
635116
671190
653153
275
1973
0,4
3,0
Total
37853
169400
1,4
6,1
TMT
103,5
446,1
TMT: Sum of age-specific mobility rates

52. Gross Migaproduction Rate: meaning
Gross Migaproduction Rate = GMR
GMR = 446,1 per 1000 resident
that’s 0,446 per capita, in other words the number of the “moves” attributed to a person during his “fictitious” life

53. B. Distance and direction of flow origin and destination of the migration flows is specified
Model and method → gravitational model, log-linear model