Birth rates

Examples of Birth rates in the following topics:

• The Demographic Transition

  • The demographic transition is a model and theory describing the transition from high birth rates and death rates to low birth and death rates that occurs as part of the economic development of a country.
  • In pre-industrial societies, population growth is relatively slow because both birth and death rates are high.
  • In most post-industrial societies, birth and death rates are both low.
  • This is depicted in the diagram when death rates fall in stage two but birth rates do not fall until stage three.
  • By the end of stage three, birth rates drop to fall in line with the lower death rates.

• Demographic Transition Theory

  • In stage one, pre-industrial society, death rates and birth rates are high and roughly in balance.
  • In stage three, birth rates fall.
  • The birth rate decline in developed countries started in the late 19th century in northern Europe.
  • During stage four there are both low birth rates and low death rates.
  • By the late 20th century, birth rates and death rates in developed countries leveled off at lower rates.

• Population Trends

  • The demographic transition refers to the shift from high birth rates and death rates to low birth and death rates; this occurs as part of the economic development of a country.
  • The basic premises of the theory are as follows: in pre-industrial societies, population growth is relatively slow because both birth and death rates are high; as countries develop, death rates fall faster than birth rates do, resulting in large population growth; as development stabilizes, birth rates drop off and the population stabilizes .
  • Most of the population growth in the world today comes from developing countries, most notably African countries, where birth rates have remained high.
  • Malthus argued for population control—policies intended to lower the birth rate—to avoid this happening.
  • This model illustrates the demographic transition, as birth and death rates rise and fall but eventually reach equilibrium.

• The Study of Population Dynamics

  • The key statistics demographers use are birth rates, death rates, and life expectancies; although, in practice, scientists also study immigration and emigration rates, which also affect populations.
  • For example, a large population would have a relatively-high birth rate if it has more reproductive individuals.
  • Such conditions would increase the birth rate.
  • If birth and death rates are equal, the population remains stable.
  • The population will increase if birth rates exceed death rates, but will decrease if birth rates are lower than death rates.

• Fertility

  • There are a number of different approaches to measuring fertility rate—such as crude birth rate (CBR), general fertility rate (GFR), child-woman ratio (CWR), total fertility rate (TFR), gross reproduction rate (GRR), and net reproduction rate (NRR).
  • Crude birth rate (CBR) is the number of live births in a given year per 1,000 people alive at the middle of that year.
  • The birth rate is an issue of concern for many governments and policymakers.
  • Conversely, other countries have policies to reduce the birth rate, such as China's former one-child policy.
  • There are claims that as countries go through economic development and social change, birth rate declines.

• Exponential Population Growth

  • Therefore, when calculating the growth rate of a population, the death rate (D; the number organisms that die during a particular time interval) is subtracted from the birth rate (B; the number organisms that are born during that interval).
  • where $\Delta N$ = change in number, $\Delta T$ = change in time, $B$ = birth rate, and $D$ = death rate.
  • The birth rate is usually expressed on a per capita (for each individual) basis.
  • Thus, B (birth rate) = bN (the per capita birth rate "b" multiplied by the number of individuals "N") and D (death rate) = dN (the per capita death rate "d" multiplied by the number of individuals "N").
  • The difference between birth and death rates is further simplified by substituting the term "r" (intrinsic rate of increase) for the relationship between birth and death rates:

• Problems in Forecasting Population Growth

  • Population growth is difficult to predict because unforeseen events can alter birth rates, death rates, migration, or resource limitations.
  • Population growth is difficult to predict because unforeseen events can alter birth rates, death rates, migration, or the resource limits on population growth.
  • Birth rates may decline faster than predicted due to increased access to contraception, later ages of marriage, the growing desire of many women in such settings to seek careers outside of child rearing and domestic work, and the decreased economic "utility" of children in industrialized settings.
  • Fertility rates could be significantly reduced by providing education about overpopulation, family planning, and birth control methods, and by making birth-control devices like male/female condoms, pills, and intrauterine devices easily available.
  • Explain the various ways sociologist try to estimate the rate of population growth, such as through fertility, birth and death rates

• The Baby Boom

  • There is some disagreement as to the precise beginning and ending dates of the post-war boom, but most agree that it began in the years immediately after the war ceased and ended more than a decade later—birth rates in the United States started to decline in 1957.
  • In 1946, live births in the United States surged from 222,721 in January to 339,499 in October.
  • An estimated 77.3 million Americans were born during this demographic boom in births.
  • The "birth boom" of the post-war period is as much defined by the deaths that preceded and followed it as it is by an exceptionally high fertility rate.
  • Compared to birth rates from 1946 to 1964, the birth rates prior to World War I (which began in 1914) were much lower, although they were still higher than the rates immediately preceding and following the 1946–1964 period.

• Three Demographic Variables

  • The basics of demographic population growth depend on the rate of natural increase (births versus deaths) and net migration.
  • Human population growth depends on the rate of natural increase, or the fertility rate minus the mortality rate, and net migration.
  • (Births - Deaths) +/- ((In-Migration) - (Out Migration)) = Population Change.
  • As this equation shows, population change depends on three variables: (1) the natural increase changes seen in birth rates, (2) the natural decrease changes seen in death rates, and (3) the changes seen in migration.
  • Natural increase refers to the increase in population not due to migration, and it can be calculated with the fertility rate and the mortality rate.

• Contraception and Birth Control

  • Contraception, also known as birth control, is methods used to prevent pregnancy; some of these methods are more successful than others.
  • Contraception, also known as birth control, is methods or devices used to prevent pregnancy.
  • The method of administering the hormone affects failure rate, although, in general, hormonal methods have a failure rate of 8%.
  • Both of these procedures have a less than 1% failure rate.
  • Describe the various methods of birth control and their associated failure rates