Understanding Population Dynamics: Key Demographic Variables
Demographic Dynamics: Key Variables
Demographic dynamics study the changes that occur over time in the size, structure, and geographical distribution of populations. These changes are primarily driven by fertility, mortality, and migration.
Population Growth
Population growth can be categorized as:
- Natural or vegetative growth: The balance between births and deaths between two different dates.
- Total or net growth: Natural growth plus net migration.
Mortality
Mortality is the set of deaths in a population during a specific period. It is a crucial demographic factor and a key indicator of a population’s health status. Mortality data is unique because it offers total population coverage and uses an internationally comparable classification and coding system.
Uses of Mortality Data
- Provides indicators of living standards and population health.
- Helps predict future trends.
- Determines health needs by highlighting excess mortality.
- Facilitates causal research.
Sources of Mortality Information
Mortality information is primarily gathered from mortality records and death certificates. In Andalusia, the Mortality Register (RMA), established in 1992, is responsible for coding causes of death and improving the quality of mortality statistics.
Mortality Indicators
Crude death rate or mortality rate:
- Specific central rates of mortality:
By age:
By sex:
Male mortality index:
- Other: Marital Status
Life Expectancy and Years of Potential Life Lost
Life expectancy is the average number of years a person is expected to live from a particular age or at birth. Years of Potential Life Lost (YPLL) is another important metric related to mortality.
Mortality by Cause of Death
Cause-specific mortality structure:
MIPS (Unnecessarily Premature and Avoidable Mortality)
Infant Mortality
- Neonatal mortality:
- Early: From 0 to 7 days
- Delayed: From 7 to 28 days
- Post-neonatal mortality: From 28 days to 12 months
Fertility
Fertility refers to the biological capacity to procreate. Fecundity is the measurement, in qualitative and quantitative aspects, of all phenomena related to fertility. It refers to the part of the population living in childbearing years. Birth rate is the frequency of births in relation to the total population.
Sources of Fertility Information
Fertility data is collected from birth records, sample surveys, and population censuses when reliable statistics are unavailable.
Fertility Indicators
Gross or crude birth rate:
General fertility rate:
General fertility rate by age:
Factors Influencing Fertility
- Extrinsic factors: Marriage, divorce, educational level, occupation, place of residence, role of women, religious beliefs, and the perceived value of children.
- Intrinsic factors:
- Physiological: Fertility, infertility, the probability of conception resulting in a live birth, and the interval of occurrence of ovulation after childbirth.
- Behavioral: Sexual practices, breastfeeding practices, contraception, and induced abortion.
Migratory Movements
Migratory movements involve the movement of people resulting in a change of habitual residence. There are two main types:
- International: Intercontinental or intracontinental.
- Internal: From rural to urban areas or from urban areas to rural communities.
Migration Indicators
Emigration rate:
Immigration rate:
