Evaluation of Internal Migration Data Collected from Population

  • Slides: 28
Download presentation
Evaluation of Internal Migration Data Collected from Population Censuses United Nations Statistics Division United

Evaluation of Internal Migration Data Collected from Population Censuses United Nations Statistics Division 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

Outline - Related concepts of internal migration - Direct and indirect estimates of internal migration - Sample tabulations - Discussion on quality issues 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”

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 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

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 United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14 -17 November 2011

Internal migration – related concepts (2) Place of usual residence (UN, 2008) It is

Internal migration – related concepts (2) 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 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

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 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

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 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 -

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 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

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 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

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 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 (3) Intercensal migration

Internal migration data from censuses – direct method place of birth (3) Intercensal migration can be estimated by using data by place of birth from two consecutive censuses Net migration for an area M = (It+n-Ot+n) – (S 1 It – S 2 Ot ) It: life time in-migrants at time t It+n: life time in-migrants at time t+n Ot: life time out-migrants at time t Ot+n: life time out-migrants at time t+n S 1: proportion of life time in-migrants It that will survive to time t+n S 2: proportion of life time out-migrants t that will survive to time t+n 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

Internal migration data from censuses – direct method place of birth (4) Source: Manual VI: Methods of Measuring Internal Migration, United Nations, 1970 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:

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 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

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 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

Internal migration data from censuses – direct method residence at a fixed past date (1) Source: Statistics Bureau of Japan 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

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. 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

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 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

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 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

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 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

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 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

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) 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) •

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 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 (2) •

Internal migration data from censuses – indirect method National growth rate method (2) • National growth rate method – example Population Rate of Net Internal Migration 2001 1991 Austria: Burgenland 277569 270880 -0. 0057 Austria: Corinthia 559404 547798 -0. 0092 1545804 1473813 0. 0184 515327 482365 0. 0379 Austria: Styria 1183303 1184720 -0. 0316 Austria: Tirol 673504 631410 0. 0363 Austria: Upper Austria 1376797 1333480 0. 0021 Austria: Vienne 1550123 1539848 -0. 0237 351095 331472 0. 0288 8032926 7795786 Austria: Lower Austria: Salzburg Austria: Vorarlberg Austria: Total Data source: graph produced based on data from United Nations Demographic Yearbook United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14 -17 November 2011

Internal migration data from censuses – indirect method Vital statistics method (1) Vital statistics

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

Internal migration data from censuses – indirect method Vital statistics method (2) Vital statistics

Internal migration data from censuses – indirect method Vital statistics method (2) Vital statistics method – example Population Rate of net migration 2001 1991 Austria: Burgenland 277569 270880 0. 0159 Austria: Corinthia 559404 547798 0. 0124 1545804 1473813 0. 0401 515327 482365 0. 0596 Austria: Styria 1183303 1184720 -0. 0100 Austria: Tirol 673504 631410 0. 0579 Austria: Upper Austria 1376797 1333480 0. 0237 Austria: Vienne 1550123 1539848 -0. 0021 351095 331472 0. 0504 8032926 7795786 Austria: Lower Austria: Salzburg Austria: Vorarlberg Austria: Total Data source: graph produced based on data from United Nations Demographic Yearbook 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 (1) Survival-rate method

Internal migration data from censuses – indirect method Survival rate method (1) 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 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

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 2001 expected survivors Net migration (1) (2) (3) (4) (5) (6) = (2)*(3) (7) = (5) - (6) 0 -4 39, 766 0. 99622529 10 - 14 38, 867 39616 -749 5 -9 36, 574 0. 991467948 15 - 19 38, 979 36262 2, 717 10 - 14 34, 289 0. 988364131 20 - 24 42, 705 33890 8, 815 15 - 19 40, 166 0. 987782981 25 - 29 54, 108 39675 14, 433 20 - 24 62, 313 0. 985758641 30 - 34 69, 222 61426 7, 796 25 - 29 72, 289 0. 980066411 35 - 39 71, 228 70848 380 30 - 34 62, 655 0. 969033736 40 - 44 59, 845 60715 -870 35 - 39 51, 290 0. 951866079 45 - 49 49, 023 48821 202 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 40445 928 55 - 59 32, 213 0. 749135574 65 - 69 25, 381 24132 1, 249 60 - 64 33, 819 0. 639850773 70 - 74 24, 730 21639 3, 091 65 - 69 30, 831 0. 488011131 75 - 79 19, 593 15046 4, 547 70 - 74 19, 021 0. 399270089 80 - 84 9, 472 7595 1, 877 75 - 79 18, 050 0. 33555271 85 - 89 5, 486 6057 -571 80 + 19, 832 0. 204715764 90+ 2, 336 4060 -1, 724 All ages 714, 525 Total 10+ 653, 617 612241 41376 United Nations Sub-Regional Workshop on Census Data Evaluation Tabulated based on data obtained Phnom Penh, Cambodia, 14 -17 November 2011 from Austria Statistics Office online database

Possible concerns/errors to use indirect method • Change of area boundaries • Mixture with

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 United Nations Sub-Regional Workshop on Census Data Evaluation Phnom Penh, Cambodia, 14 -17 November 2011