1. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Evaluation of Internal Migration Data Collected from Population Censuses United Nations Statistics Division

2. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Outline -Related concepts of internal migration -Direct and indirect estimates of internal migration -Sample tabulations -Discussion on quality issues

3. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration – related concepts -Mobility versus migration -Migration refers to “long-distance” move, i.e., moves across states or county lines (usually referring to across administrative unit borders) -Migration  change of place of usual residence -Time element -Geographic moves

4. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration – related concept short and long distance moves Data source: Methods and Materials of Demography, classification based on “1-year” data from the March 2000 Current Population Survey of the US

5. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Place of usual residence (UN, 2008) It is recommended that countries apply a threshold of 12 months when considering place of usual residence according to one of the following two criteria: (a)The place at which the person has lived continuously for most of the last 12 months (that is, for at least six months and one day), not including temporary absences for holidays or work assignments, or intends to live for at least six months; (b) The place at which the person has lived continuously for at least the last 12 months, not including temporary absences for holidays or work assignments, or intends to live for at least 12 months. Difficult to treat groups: -Seasonal residence -work in one place during weekdays and join family member during weekends -College students Internal migration – related concepts (2)

6. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration – related concepts (3) Lifetime migration: - Migration occurred between birth and the time of the census Recent migration: - Migration occurred in recent period, e.g., 1 year

7. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses -Tabulated from direct questions about mobility or about prior residence -Place of birth -Place of residence at a fixed past date -Duration of residence -Previous place of residence -Estimates of net migration derived from (residual estimates) -Counts of total population or population disaggregated by age and sex, at two censuses -Natural increase or intercensal survival rates, which are derived in turn from (a) life tables or (b) comparison of the age distributions of countries not experiencing immigration or emigration in successive censuses

8. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method -Place of birth -Civil division of birth for native-borns; usually refers to the geographical unit of the country in which the mother resides at the time of the person’s birth -Country if foreign-born -Place of residence at a specified date in the past -Major or smaller division, or a foreign country -1 or 5 years, or both -1 year easier to recall -Different date may be used depends on national circumstances -Duration of residence -Should refer to the length of residence in the major or smaller civil divisions and the locality, but not in the particular housing unit -Place of previous residence -Major or smaller division, or a foreign country

9. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method place of birth (1) Source: The Methods and Materials of Demography, 2 nd edition, Siegel and Swanson, 2004

10. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method place of birth (2) Source: The Methods and Materials of Demography, 2 nd edition, Siegel and Swanson, 2004

11. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Intercensal migration can be estimated by using data by place of birth from two consecutive censuses Net migration for an area M = (I t+n -O t+n ) – (S 1 I t – S 2 O t ) I t : life time in-migrants at time t I t+n : life time in-migrants at time t+n O t : life time out-migrants at time t O t+n : life time out-migrants at time t+n S 1 : proportion of life time in-migrants I t that will survive to time t+n S 2 : proportion of life time out-migrants t that will survive to time t+n Internal migration data from censuses – direct method place of birth (3)

12. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method place of birth (4) Source: Manual VI: Methods of Measuring Internal Migration, United Nations, 1970

13. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method place of birth (5) Quality issues: -Memory problem -Uncertainties about area boundaries at the time of birth -Errors in reporting of birthplaces for babies who were not born at the usual residence of their parents -Reporting birthplace according to the old administrative boundaries -Reporting place of births like hospitals rather than place of usual residence of the mother

14. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method place of birth (6) Ways to assess data quality: -re-interviews or matching studies of a sample of the original records (US census Bureau, 1995, p.19) -Study the impact of boundary changes: -Lee et al. 1957 -Compare between censuses or with household surveys

15. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method residence at a fixed past date (1) Source: Statistics Bureau of Japan

16. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method residence at a fixed past date (3) Information may be used to get a sense of “flow”: annual in-migrants and out-migrants for different areas.

17. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method residence at a fixed past date (4) Quality issues: -Memory problem, the longer the period used, the less accurate the information is -Mis-reporting of previous residence -Change of boundaries

18. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method duration of residence + previous residence (1) Distribution of lifetime migrants by duration of stay in each State Source: Manual VI: Methods of Measuring Internal Migration, United Nations, 1970

19. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method duration of residence + previous residence (2) For recent migrants: longer distance  more migrants Source: Manual VI: Methods of Measuring Internal Migration, United Nations, 1970

20. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method duration of residence + previous residence (3) Origin, destination and time of migration (duration): Source: Manual VI: Methods of Measuring Internal Migration, United Nations, 1970

21. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – direct method duration of residence + previous residence (4) Quality issues: -Memory problem, might not remember when moved -Digit preference (similar to those reflected in age-reporting)

22. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – indirect method National growth rate method (1) National growth rate method – for net internal migration Population of area i in the first census Population of area i in the second census Total population of a country in the first census Positive rate: with net inmigration; negative rate: net outmigration Assumes same natural increase rate and net immigration from abroad for all parts of the country

23. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 National growth rate method – example Population Rate of Net Internal Migration 20011991 Austria: Burgenland277569270880-0.0057 Austria: Corinthia559404547798-0.0092 Austria: Lower Austria154580414738130.0184 Austria: Salzburg5153274823650.0379 Austria: Styria11833031184720-0.0316 Austria: Tirol6735046314100.0363 Austria: Upper Austria137679713334800.0021 Austria: Vienne15501231539848-0.0237 Austria: Vorarlberg3510953314720.0288 Austria: Total80329267795786 Internal migration data from censuses – indirect method National growth rate method (2) Data source: graph produced based on data from United Nations Demographic Yearbook

24. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Vital statistics method for net migration rate Births nationally during the intercensal period Deaths nationally during the intercensal period Assumes same natural increase rate across all areas Calculate net migration rate (incl. both internal and international migration) Internal migration data from censuses – indirect method Vital statistics method (1)

25. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Population Rate of net migration 20011991 Austria: Burgenland2775692708800.0159 Austria: Corinthia5594045477980.0124 Austria: Lower Austria154580414738130.0401 Austria: Salzburg5153274823650.0596 Austria: Styria11833031184720-0.0100 Austria: Tirol6735046314100.0579 Austria: Upper Austria137679713334800.0237 Austria: Vienne15501231539848-0.0021 Austria: Vorarlberg3510953314720.0504 Austria: Total80329267795786 Vital statistics method – example Internal migration data from censuses – indirect method Vital statistics method (2) Data source: graph produced based on data from United Nations Demographic Yearbook

26. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Survival-rate method Net migration for the cohort aged x at year 0 to year t Population size for cohort x (at year 0) at year t Survival rate of the cohort from year 0 to year t Population size for cohort x at year 0 Adjustment for deaths of migrants during the period s can be calculated by Internal migration data from censuses – indirect method Survival rate method (1)

27. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Internal migration data from censuses – indirect method Survival rate method (2): Vienna, Austria Age Population in 1991 10-year life table survival ratio Age Population in 2001expected survivors Net migration (1) (2)(3) (4) (5)(6) = (2)*(3)(7) = (5) - (6) 0 - 439,766 0.99622529 10 - 14 38,867 39616-749 5 - 9 36,574 0.991467948 15 - 19 38,979 362622,717 10 - 14 34,289 0.988364131 20 - 24 42,705 338908,815 15 - 19 40,166 0.987782981 25 - 29 54,108 3967514,433 20 - 24 62,313 0.985758641 30 - 34 69,222 614267,796 25 - 29 72,289 0.980066411 35 - 39 71,228 70848380 30 - 34 62,655 0.969033736 40 - 44 59,845 60715-870 35 - 39 51,290 0.951866079 45 - 49 49,023 48821202 40 - 44 56,236 0.927062515 50 - 54 51,774 52134-360 45 - 49 56,240 0.886929277 55 - 59 49,495 49881-386 50 - 54 48,941 0.826409977 60 - 64 41,373 40445928 55 - 59 32,213 0.749135574 65 - 69 25,381 241321,249 60 - 64 33,819 0.639850773 70 - 74 24,730 216393,091 65 - 69 30,831 0.488011131 75 - 79 19,593 150464,547 70 - 74 19,021 0.399270089 80 - 849,472 75951,877 75 - 79 18,050 0.33555271 85 - 895,486 6057-571 80 + 19,832 0.204715764 90+2,336 4060-1,724 All ages714,525 Total 10+ 653,617 61224141376 Tabulated based on data obtained from Austria Statistics Office online database

28. United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14-17 November 2011 Possible concerns/errors to use indirect method Change of area boundaries Mixture with international migration Depends on errors in all components: Population by age and sex Births Deaths