Census and Age Structure Flashcards
Population (empirical population defintion)
collection of people alive at a specified point in time who meet certain criteria
Population (conceptual population definition)
collectivity of people that persists over time even though its members are always changing
Important characteristics of populations
size, composition, distribution, dynamics (changes over time)
Growth balance equation
PopulationT2 = populationT1 + B - D + I - O
What do I and O stand for in the population migration equation
In migration and out migration
Natural increase/decrease
B - D (babies born - deaths)
Net migration
I - O
Demographic rates
a fraction to measure events (only applicable to the empirical definition of population)
How to set up a demographic rate
Numerator: What event are we measuring and over what time period
Denominator: Who is at risk of experiencing an event
Person years of exposure
the population’s amount of exposure to the risk of the event
Rate of population growth
(P2 - P1)/P1
Crude birth rate
births/P1
Crude death rate
deaths/P1
Rate of net migration
(I-O)/P1
Goal of the census
gain a full count of the alive population on a specific date
What are the impacts of the census
allocation of representatives, allocation of federal funding
Problems with data collection for the census
bias (statistical errors, not beliefs), response rates, only head of households fill out the form, undercounted populations
Vital registration system
formal, bureaucratic system for recording births and deaths
Excess mortality
compare expected to observed number of deaths (regardless of causes)
P score of mortality
the difference between expected and actual percentages of deaths
Error of closure
X, people who were missed during the counting leading to errors in data
Population age structure
the number of people in the population at a certain age
Population pyramids
Breaks the population down by age and sex, a visual
Abridged population pyramid
combines age into 5 year increments, most common
Features of young population pyramids
curved inwards and skinny
Features of mature population pyramids
smaller at the bottom than in the middle/top, relative same birth rate each year
Features of old population pyramids
birth cohorts are similar in size and improving survival at several ages
Features of undercut population pyramids
more recent birth cohorts are smaller than previous
Features of declining population pyramids
have a sustained undercut (birth cohorts are getting smaller)
Features of unimodal population pyramids
one age is much more prevalent than the others, could be from college towns, military towns
Baby boom echo
there are more people having babies at a certain age due to the original baby boom leading to an echo
Features of slow growth population pyramids
column shape that is smaller at the top
Features of negative growth population pyramids
narrowing, undercut base of the pyramid
Dependency ratio
the ratio of dependents (0-15; >64) to working class
Demographic dividend
a period when the labor force grows much more than the demographic that depends on it
Demographic implosion
a lot of resources going to care and not other resources so many people need to take care of the elderly
Population projection
Using information about past population patterns and applying it to current population numbers
Cohort component projection
an extension of the super basic population projections on specific cohorts of people (usually age specific)
Social statistics infrastructure
Features in society that benefit social welfare such as weather warnings and economic forecasts
