Regional workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October Evaluation and Analysis of Age and Sex Structure François Pelletier & Thomas Spoorenberg Population Estimates and Projections Section Evaluation method of age and sex distribution data ° Basic graphical tools o Graphical analysis • Population pyramids • Graphical cohort analysis o Age and sex ratios o Summary indices of error in age-sex data • Whipple ’s index • Myers ’ Blended Method Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Importance of age-sex structure ° 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 o Determined by fertility, mortality and migration, and follows fairly recognizable patterns Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 What to look for at the evaluation ° Possible data errors in the age-sex structure, including o Age misreporting (age heaping and/or age exaggeration) o Coverage errors – net underenumeration (by age or sex) ° Significant discrepancies in age-sex structure due to extraordinary events o High migration, war, famine, HIV/AIDS epidemic etc. Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 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 o The date of birth (year, month and day) - more precise information and is preferred o 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 Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 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 Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Population pyramid – France, 1954 (Source : Pison 2014) Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Population pyramid – France, 1974 (Source : Pison 2014) Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Population pyramid – France, 2014 (Source : Pison 2014) Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Population pyramid – High population growth Age Central African Republic, 1988 Census 95+ 90 MALE FEMALE 85 80 75 70 65 60 55 50 45 40 35 30 25 20 Wide base, triangle-shaped 15 pyramid indicates high fertility 10 5 0 50,000 25,000 0 25,000 50,000 Population Source : United Nations Statistics Division, Demographic Yearbook Statistical Database Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Population pyramid – Low population growth Age Italy, 2011 Census 95+ 90 MALE FEMALE 85 80 75 70 1940-45 Birth deficit 65 due to WWII 60 “baby boom” 55 50 45 40 35 30 25 20 15 Flattening and narrowing base 10 Indicates long-term low fertility 5 0 500,000 300,000 100,000 100,000 300,000 500,000 Population Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Age YEMEN, 1975 Census Population pyramid – Detecting errors 85+ 80-84 75-79 MALE FEMALE 70-74 65-69 60-64 Age 55-59 YEMEN, 1975 Census 50-54 85+ 45-49 80 40-44 MALE FEMALE 35-39 75 30-34 25-29 70 20-24 65 15-19 10-14 60 5-9 55 0-4 50 1,500,000 750,000Population 0 750,000 1,500,000 45 40 35 ° Age misreporting errors (heaping) among adults 30 25 ° Under enumeration of young children (< age 2) 20 15 ° High fertility level 10 5 ° Smaller population in 20-24 age group 0 >> extraordinary events in 1950-55? 320,000 220,000 120,000 20,000 80,000 180,000 280,000 Population ° Less men relative to women in 20-44 age group >> labor out-migration? Source : United Nations Statistics Division, Demographic Yearbook Statistical Database Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Population pyramid – Detecting errors Age TUNISIA, 1966 Census 100+ 95 90 MALE FEMALE 85 Age TUNISIA, 1994 Census 80 100+ 75 95 70 90 MALE FEMALE 65 Age heaping 85 60 80 55 75 50 70 45 65 40 60 35 55 30 50 25 45 20 40 15 35 10 30 5 25 0 20 100,00075,000 50,000 25,000 0 25,000 50,000 75,000100,000 15 Population 10 5 Declining fertility 0 120,00090,000 60,000 30,000 0 30,000 60,000 90,000120,000 Population Source : United Nations Statistics Division, Demographic Yearbook Statistical Database Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Population pyramid – Detecting errors Age Bahrain, 2010 Census Age U.A.E., 2005 Census 85+ 80 MALE FEMALE 80-84 75 MALE FEMALE 70 70-74 65 60 60-64 55 50 50-54 45 40 40-44 35 30 30-34 25 20 20-24 15 10 10-14 5 0 0-4 30,000 20,000 10,000 0 10,000 20,000 30,000 500,000 300,000 100,000 100,000 300,000 500,000 Population Population !!! Effect of Labor migration !!! >> Importance of knowledge of the context Source : United Nations Statistics Division, Demographic Yearbook Statistical Database Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Population pyramid – Line instead of bars ° Population Pyramid (bar chart) >> Not always easy to determine differences by sex ° Use of line chart Bangladesh, 2001 Census 3,000,000 Age Bangladesh, 2001 Census 85+ Male 80 FEMALE 2,500,000 75 MALE Female 70 65 2,000,000 60 55 50 45 1,500,000 40 35 Population 30 1,000,000 25 20 15 500,000 10 5 0 0 3,000,000 1,500,000 0 1,500,000 3,000,000 Population 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80+ Age Source : United Nations Statistics Division, Demographic Yearbook Statistical Database Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Population pyramid – Line instead of bars Bangladesh, 2001 Census Bangladesh, 2001 Census 3,000,000 9,000,000 Male 8,000,000 Male 2,500,000 Female 7,000,000 Female 6,000,000 2,000,000 5,000,000 1,500,000 4,000,000 Population Population 3,000,000 1,000,000 2,000,000 500,000 1,000,000 0 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 7580+ Age Age group Source : United Nations Statistics Division, Demographic Yearbook Statistical Database Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 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 Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Graphical cohort analysis – Example (1) Mozambique, 1997 and 2007 Censuses 1997 Census 2007 Census Birth Cohort Male Female Male Female 0-4 1,353,206 1,388,350 2002-2007 5-9 1,112,321 1,113,675 1997-2001 ° Data is organized by birth 10-14 947,236 878,429 1,222,668 1,183,939 1992-1997 cohort 15-19 774,327 854,078 925,729 991,323 1987-1992 ° Exclude open-ended age 20-24 637,113 827,614 774,413 986,526 1982-1997 25-29 509,109 654,465 707,603 841,416 1977-1982 category 30-34 410,148 477,562 583,689 667,865 1972-1977 ° People who were born in 35-39 373,813 428,395 481,396 556,191 1967-1972 40-44 270,046 303,147 366,518 389,087 1962-1967 the same years are 45-49 257,070 282,098 321,236 328,660 1957-1962 compared in the analysis 50-54 178,902 212,060 231,232 283,288 1952-1957 55-59 162,122 174,234 194,011 208,657 1947-1952 60-64 114,335 125,096 140,146 159,557 1942-1947 65-69 100,425 109,288 113,840 127,794 1937-1942 70-74 47,407 50,607 72,288 81,329 1932-1937 75-79 41,529 42,858 55,448 61,012 1927-1932 Source : United Nations Statistics Division, 80-84 15,305 17,326 22,417 28,278 1922-1927 Demographic Yearbook Statistical 85-89 16,576 19,448 1917-1922 Database 90-94 4,803 5,883 1912-1917 Regional Workshop on the Production of Population Estimates and Demographic Indicators Addis Ababa, 5-9 October 2015 Population 1,000,000 1,200,000 1,400,000 1,600,000 Source 200,000 400,000 600,000 800,000 Graphical Graphical analysis cohort – Example (1) Mozambique, 1997