LONG YAV Master of Population Studies (Demography)

Demography is derived from the Greek word “Demo” meaning human being or human population. This term seems to have been coined for the first time by a Belgian statistician Achille Guillard in 1855 in the article entitled “Eléments de statistique humaine, ou démographique comparée” (Shryock and Siegel, 1971) The study of human population is known by two terms: Demography and Population studies and these two terms are often used interchangeably. LONG YAV Master of Population Studies (Demography)

 Demography: A scientific study of human population focusing on population size, population structure or composition, population events and population characteristics.  Population studies: The study of the relationship between demographic variables and other variables such as social and economic variables. LONG YAV Master of Population Studies (Demography)

Other definitions of demography:  The empirical, statistical and mathematical study of human population: changes in size, composition, & distribution of population in space.  The quantitative study of demographic processes: fertility, mortality, marriage, and migration LONG YAV Master of Population Studies (Demography)

Population studies emerged as a discipline in England in the middle of the 17 century.  John Graunt: Natural and Political Observations made upon the Bills of mortality, published in London in His observations mainly contained a quantitative analysis of mortality.  Edmund Halley ( ), an English astronomer, constructed the first empirical life table in 1693 based on the data of births and deaths. LONG YAV Master of Population Studies (Demography)

 Gregory King ( ), another English scholar contributes to the discipline by estimating the population of England and Wales.  Achille Guillard ( ) wrote an article “Eléments de statistique humaine ou démographique comparée”(Elements of human statistics or comparative demography).  Some scholars in eighteen century observed the relationship between the potentiality of population growth and available resources and arrived at the conclusion that the potentialities of human population growth might surpass the resources required for its support e.g. Hung Liang-Chi and Thomas R. Malthus. LONG YAV Master of Population Studies (Demography)

 Hung Liang-Chi, noted that an increased in the means of subsistence was not in direct proportion to that of the population in the eighteenth century.  Godwin, M. Condorcet and other writers by Thomas R. Malthus ( ) wrote an essay in 1798 on principles of population stating that man could increase his subsistence only in arithmetical progression and his numbers tended to increase in geometrical progression.  The United States of America had its first census in 1790 and England and France in  In 1922, A.M. Carr-Saunders, a biologist, published his book, the population problem, containing a systematic statement of the problems of population size and growth and a discussion of the genetic question. LONG YAV Master of Population Studies (Demography)

DEMOGRAPHY STATITICS SOCIOLOGY BIOLOGYECONOMICS LAW GEOGRAPHYMATHEMATICS Fertility with connect to attitudes & social institutions Population Policy/law: Fertility, mortality, migration, health, sanitation etc. Mathematic Model to est. population growth Population & Development, man power study FP, fertility regulation & RH behavior of individuals Geographical population distribution & its movement Fecundity, SR & age-sex diff. in Mortality Theory of Probability on Mortality PSYCHOLOGY LONG YAV Master of Population Studies (Demography)

Population Census, Vital Registration & Sample Survey LONG YAV Master of Population Studies (Demography) 1. Population Census: The total process of collecting, compiling and publishing of demographic, economic and social data pertaining to a specify time or times of all persons in a country or delimited territory (The United Nations).  Essential Characteristics: Universality, Simultaneity, and Individual enumeration

History of Census  Census is derived from Greece word Censere, meaning to value or tax: Egypt 3000 B.C.“Census” every other year. They list of families and other occupants of houses for certain particular cases (e.g., soldiers) Greece: count of males 18 years and older Rome: Enumeration of every family every five years for taxation purposes. Modern census Format emerged gradually around 1600s in Europe. Quebec 1666 LONG YAV Master of Population Studies (Demography)

 Census can be conducted in every 5 or 10 years: - De facto: count population according to where they are staying at the time of census enumeration or the night before, irrespective of their usual place of residence. - De jure: collect information about all the persons who usually live in a household, whether or not they are present at the time of enumeration. LONG YAV Master of Population Studies (Demography)

 Establish administrative tree (census officers, supervisors, enumerators)  Develop questionnaire(s)  Cartography  Define enumeration areas  Pretest enumeration processes  Design data processing system  Enumeration (postal with follow-up, general canvas) LONG YAV Master of Population Studies (Demography)

 Census contains 1. Demographic data e.g., age and sex 2. Economic data e.g., occupation and income 3. Social data e.g., education and housing  Census record information at: 1. Individual Level: name, age, sex, relationship to the head of household, marital status, religion, education, employment status, occupation and migration etc. 2. Household Level: housing condition and amenities, # of children ever born, children still alive and the births during the one year period during the census time, and employment status etc. LONG YAV Master of Population Studies (Demography)

Advantages  Universal, hence small area data available  National effort  Provides frame for later sample surveys  Provides population denominators Disadvantages  Size limits content and quality control efforts  Cost limits frequency  Delay between field work and results  Sometimes politicized LONG YAV Master of Population Studies (Demography)

 Sample Survey involves taking a sample of the population to be enumerated with more trained investigators interviewing them more intensely in a few selected areas.  Purposes: Obtain information from a sample representative of some population.  Essential Characteristics: 1. Representative sample of some population 2. Smaller size than census allows collection of more in- depth information that can then be generalized LONG YAV Master of Population Studies (Demography) 2. Sample Survey

Two types of sample survey: 1. Single-round retrospective  Census-type household surveys  Focused, (e.g., Contraceptive Prevalence Survey (CPS))  Birth/Maternity history (World Fertility Survey (WFS), Demographic and Health Survey (DHS)) 2. Multi-round follow-up (prospective) LONG YAV Master of Population Studies (Demography)

 Sampling frame, generally from census  Separate strata are often defined for sampling. The provinces, urban and rural areas could be strata.  Sample size depends on resources and timing but it has to be representative so that the result can be generalized  Sample size calculation: where LONG YAV Master of Population Studies (Demography) n = Z 2 *p*q / D 2 n= The sample size z= The number that matches the CI. Z=1.96 if the 95% CI and z=1.645 for 90%CI D= The maximum margin of error you decided could be accepted, either.05 or.10 p= The estimated proportion you will be measuring. If you do not know the p value, just put it.5 meaning 50% q=1-p

Advantages 1. Single-round retrospective: Can be quick, relatively inexpensive, flexible, can include detailed data, needs little continuity effort 2. Multi-round prospective  Some control on coverage and content errors  Follow-up allows control for sampling distortion LONG YAV Master of Population Studies (Demography) Disadvantages: 1. Single-round retrospective: Coverage and content errors, Misses certain types of events 2. Multi-round prospective: Slow, Needs continuity of effort over (extended) time, High cost

 A system to register demographic events such as birth, death and marriage.  Purposes: Administrative and legal purposes. Help to understand demographic characteristics of different populations at different points in time.  Essential Characteristics: Universality & Continuity LONG YAV Master of Population Studies (Demography) 3. Vital Registration

 Live birth—Complete expulsion or extraction from its mother of a product of conception, irrespective of the duration of pregnancy, which after such separation, breathes or shows any other evidence of life such as beating of the heart, pulsation of the umbilical cord.  All live-born infants should be registered as live birth irrespective of gestation age.  The United Nations recommended to register date and place of occurrence, date of registration, type of birth or delivery, sex of the child, weight of the child at birth, legitimacy status, and characteristics of the mother (name, age or date of birth, date or duration of marriage, place of usual residence). LONG YAV Master of Population Studies (Demography) a. Live birth registration

 Death: WHO defines death as permanent disappearance of all evidence of life at any time after live birth has taken place  The death is indicated by the lost of evidence of life such as breathing, beating of the heart etc.  The United Nations recommended to register date and place of occurrence, date of registration, cause of death, certifier, age or date of birth, sex and marital status, occupation, place of usual residence). LONG YAV Master of Population Studies (Demography) b. Death registration

 Marriage—Ceremony or process by which the legal relationship of husband and wife is constituted.  The legality of the union may be established by civil, religious, or other means as recognized by the laws of each country.  The United Nations recommended to register date and place of occurrence, date of registration, type of marriage (civil, religious, customary), and data on bride and groom such as age or date of birth, previous marital status, place of usual residence). LONG YAV Master of Population Studies (Demography) c. Marriage registration

Advantages  Continuous monitoring of vital rates  May provide both numerator & denominator for rates (e.g., IMR)  Small area data available  Base for testing the accuracy of censuses and surveys Disadvantages  Uncertain coverage: Difficult to ensure registration of all the events  Limited background information  Time reference often inconsistent with denominator definition  Information may come from third party  Easily disrupted by political/economic events  Literacy/numeracy  Costly LONG YAV Master of Population Studies (Demography) Advantages & disadvantages of vital registration

1.Cambodia Population Census in 2008, 1998 & Cambodia Population Projection 2008 and Cambodia Inter-Census in Population count in 1992 by UNTAC 5.Population count in Cambodia Demographic and Health survey (CDHS) in 2010, 2005 and Cambodia Socio-Economic Survey (CSES) conducted firstly in The CSES has been conducting annually since LONG YAV Master of Population Studies (Demography) Cambodian Demographic Data sources

THANKS FOR YOUR ATTENTION! LONG YAV Master of Population Studies (Demography)