Demography and Population studies

DEMOGRAPHY AND POPULATION STUDIES
Demography – refers to the analysis (increase and decrease of population)
Why do we need to study population?
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To understand the changes of population
Demographic – description of people (based on the number)
– analysis on the size, composition of population
Demos – means people; Graphos – means to write
Aspects of Human Population
1. Size – number of population in an area at a given point time
2. Composition – ascribed and achieved
Occupation, marital status, educational attainment
(there is change & cannot be predictable)
Age, sex, birth (they are either never
change, if it changes it is predictable
3. Distribution – how the population is dispersed
4. Component of population – birth, death, migration (the different aspects that affect it)
5. Determinants & Consequences – consequences and effects of higher & lesser population
Sub Fields of Demography
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Formal demography – theoretical, pure or basic demography
Applied demography – pertains to population studies
Rome – conduct the first census
“to assess”
In 1900, Norway first use survey in a census
Census – is conducted every 5 years
Common terms used in Census
1. Sex & Gender
*Sex – biological
*Gender – sexual orientation
2. Age – measurement after you were born
Children – 18 below (17)
Old age – 65 up and over
Adult – legality (18)
Adolescent – 13-19
3. Birth
Elements of Population
1. Fertility and Birth
Fertility – incidence of child bearing a countless population
– affects by age, social values, religion, culture
For example: At the age of 15, she got married, higher possibility of fertility rate
Crude birth rate (CBR) – no. of livebirth in a given time
20 birth- maximum birth of a woman (from menstruation to menopause)
Fecundity – maximum no. of possible child bearing
– is affected by culture, family orientation, preference of marriage
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Not to compare birth rate because population varies from country to country but it is a good
indicator of a country’s population
2. Mortality – incidence of death
Crude death rate (CDR) – no. of death in a given time
Infant Mortality Rate (IMR)
Mortality is influenced by health services, nutrition
3. Migration – immigration and emigration
comes in
leaving/out
APPLIED DEMOGRAPHY
(population studies)
–
concerned with the application of demography
Data Collection Method
1. Census
2. Sample Survey
3. Registration of Birth, Death, Marriages and Divorces
4. Population Registers
5. Administrative Records
6. Availability of demographic data from international agencies
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Census – complete enumeration of a given population
1. enumeration of each individual in the whole population
2. universal coverage of the population within defined territory
3. specified period of time of the coverage of the whole population
4. periodic frequency
Points to Consider in Census
1. identification of each individual to avoid duplication
2. it requires the definition of the territory to be covered and parts thereof and reasonable access to people
3. should take place in a time when people re easily contacted in their usual place of residence
4. enumeration follows different rule depending on residence status
5. residence may be classified according to their usual residence
(DE JURE) or where they are at times of the census (DE FACTO)
6. population census are done in conjunction with the housing census
7. the extent of information collected varies from country to country
8. may collect information on a range of individual characteristics (e.g. sex, age, marital status, education
labor force, etc.)
9. may also be used to estimate both domestic and international migration
2 Main Kinds of ERRORS
1. OMISSION OF INDIVIDUALS FROM THE CENSUS (COVERAGE)
2. MISREPORTING OF INFORMATION BY INDIVIDUALS IN THE CENSUS (RESPONSE)
Therefore, needs:
1. Validity test (compare the last census)
2. Post Enumeration Survey
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Sample Survey – useful compliments to demographic information obtained through census and
other sources
Advantages
1. less costly
2. can be design with a specific purpose in mind
3. can dwell in depth into the subject matter
4. they can be used in combination with demographic data obtained from other sources
5. enable the estimation of the census coverage and reliability
Points to Consider in Survey
1. may have attribute of a census
2. may use a sample of the target population to assess their characteristics (probability an non probability
samples)
3. can be concerned with a variety of demographic information
4. undertaken periodically
5. precession, cost and time
6. study of trends over time and seasonality
BASIC SAMPLING CLASSIFICATION
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Probability sample – have a known chance of being selected
1.
2.
3.
4.
Simple random sampling
Systematic sampling
Cluster sampling
Stratified sampling
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Non Probability sample – unknown chance of selecting members
1.
2.
3.
4.
Convenience sampling
Judgment sampling
Referral sampling (snowball)
Quota sampling
Developing a Sample Plan
Step 1: Define the relevant population
Step 2: Obtain a population visit, if possible; may only be some type of sample frame
Step 3: Design the sample method (size & method)
Step 4: Draw the sample (substitution, oversampling, resampling)
Step 5: Assess the sample
Step 6: Resample if necessary
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Registration of Birth, Death, Marriages and Divorces
Birth Registration – date of birth, sex, parents’ details including age, usual residence, marital status and
occupation
Death Registration – records age and sex, place of birth, marital status, occupation and cause of death
Marriages & Divorces – a source of information on family relationships
Registration usually records DE JURE not DE FACTO relationships or separations
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Population Registers – provide systematic record of the identity and characteristics of each
individual resident either in a country or an area within
data recorded may include the date of birth, sex, marital status, place of birth and nationality
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Administrative Records – established for specific purposes such as government or private
activities (school records, hospital records, international arrival and departure, public utilities)
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Availability of demographic data from international agencies – major source of demographic
information are usually national agencies charged with the collection and dissemination of
statistics
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primary sources (ex. census, survey, other agency) or through publications, special
tabulations, samples of individual records in electronic media or through the internet
the UN publishes a demographic year book with statistics from member countries
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