Spatial Demography -- Population Patterns, Basic Principles

I. Definitions:

  1. Demography:  The study of population
  2. Population Geography:  Spatial aspects of demography or population, answers questions of where? And why there?
  3. Spatial Epidemiology and Medical Geography:  studies the origin and diffusion of disease.
  4. At-Risk Principle

II. Demographic Accounting Equation

  1. P(t+1)=P(t)
                                +B(t, t+1)-D(t, t-1)       natural change
                                +I(t, t+1)-E(t, t-1)        net migration
  2. Internal Migration vs. International Migration
                Internal:  Between states within a country
                International:  Between countries
  3. Composition of Migration:  Who is migrating where?
                --example:  California, most immigrants come to L.A. 

III. Constructing and Interpreting Rates

  1. Demographic Rates and Measures
    1. Rate:  the frequency of occurrence of a demographic event for a population at risk over a given time period.
    2. Crude Birth Rate (CBR):  annual number of live births per 1,000 population
    3. Crude Death Rate (CDR):  annual number of deaths per 1,000 population
    4. Total Fertility Rate (TFR):  average number of children born to each woman if during her childbearing years she bore
                      children at current years rate fro women her age.
    5. Expectancy of Life at Birth (or age X)(e0):  the amount of years you are expected to live (differs between countries).
    6. Doubling Time:  Amount of time it takes for a country to completely double its population (ln(2)/r)   
  2. Examples: 
  3. CBR > CDR      natural population increase
    CBR < CDR      natural population decrease
            Example:  Syria (CBR=33, CDR=6)
               Natural increase:  33-6=27 per 1,000 or 2.7%
               Doubling Time:  ln(2)/.027=25.7 years
            Example:  Afghanistan (CBR=42, CDR=17)
               Natural Increase:  42-17=25 per 1,000 or 2.5%
               Doubling Time:  ln(2)/.025=27.7 years
            Example:  Japan (CBR=10, CDR=8)
               Natural Increase:  10-8=2 per 1,000 or .2%
               Doubling Time: ln(2)/.002=347 years