A census is the procedure of systematically acquiring, recording and calculating population information about the members of a given population. This term is used mostly in connection with national population and housing censuses; other common censuses include censuses of agriculture, traditional culture, business, supplies, and traffic censuses. The United Nations (UN) defines the essential features of population and housing censuses as "individual enumeration, universality within a defined territory, simultaneity and defined periodicity", and recommends that population censuses be taken at least every ten years. UN recommendations also cover census topics to be collected, official definitions, classifications and other useful information to co-ordinate international practices.
India is the second most populated country in the world with a sixth of the world's population. According to official estimates in 2021, India's population stood at 1.38 billion.
Life expectancy is a statistical measure of the average time an organism is expected to live, based on the year of its birth, current age, and other demographic factors like sex. The most commonly used measure is life expectancy at birth (LEB), which can be defined in two ways. Cohort LEB is the mean length of life of a birth cohort and can be computed only for cohorts born so long ago that all their members have died. Period LEB is the mean length of life of a hypothetical cohort assumed to be exposed, from birth through death, to the mortality rates observed at a given year.
Population is the term typically used to refer to the number of people in a single area. Governments conduct a census to quantify the size of a resident population within a given jurisdiction.
The demographics of Ukraine relate to population growth, population density, ethnicity, education-level, health, economic status, religious affiliations, and other aspects of the population of Ukraine.
Demography is the statistical study of populations, especially human beings.
Epidemiology is the study and analysis of the distribution, patterns and determinants of health and disease conditions in a defined population.
The United States had an official estimated resident population of 333,287,557 on July 1, 2022, according to the U.S. Census Bureau. This figure includes the 50 states and the District of Columbia but excludes the population of five unincorporated U.S. territories as well as several minor island possessions. The United States is the third most populous country in the world. The Census Bureau showed a population increase of 0.4% for the twelve-month period ending in July 2022, below the world average annual rate of 0.9%. The total fertility rate in the United States estimated for 2021 is 1.664 children per woman, which is below the replacement fertility rate of approximately 2.1.
In demography, demographic transition is a phenomenon and theory which refers to the historical shift from high birth rates and high death rates in societies with minimal technology, education and economic development, to low birth rates and low death rates in societies with advanced technology, education and economic development, as well as the stages between these two scenarios. Although this shift has occurred in many industrialized countries, the theory and model are frequently imprecise when applied to individual countries due to specific social, political and economic factors affecting particular populations.
Fertility is the capability to produce offspring through reproduction following the onset of sexual maturity. The fertility rate is the average number of children born by a female during her lifetime and is quantified demographically. Fertility is addressed when there is a difficulty or an inability to reproduce naturally, which is referred to as infertility. Infertility is widespread, with fertility specialists available all over the world to assist mothers and couples who experience difficulties having a baby.
Wilhelm Lexis, full name Wilhelm Hector Richard Albrecht Lexis, was a German statistician, economist, and social scientist. The Oxford Dictionary of Statistics cites him as a "pioneer of the analysis of demographic time series". Lexis is largely remembered for two items that bear his name—the Lexis ratio and the Lexis diagram.
The total fertility rate (TFR) of a population is the average number of children that would be born to a woman over her lifetime if:
- she were to experience the exact current age-specific fertility rates (ASFRs) through her lifetime
- she were to live from birth until the end of her reproductive life.
A population pyramid or "age-sex pyramid" is a graphical illustration of the distribution of a population by age groups and sex; it typically takes the shape of a pyramid when the population is growing. Males are usually shown on the left and females on the right, and they may be measured in absolute numbers or as a percentage of the total population. The pyramid can be used to visualize the age of a particular population. It is also used in ecology to determine the overall age distribution of a population; an indication of the reproductive capabilities and likelihood of the continuation of a species. Number of people per unit area of land is called population density.
In actuarial science and demography, a life table is a table which shows, for each age, what the probability is that a person of that age will die before their next birthday. In other words, it represents the survivorship of people from a certain population. They can also be explained as a long-term mathematical way to measure a population's longevity. Tables have been created by demographers including Graunt, Reed and Merrell, Keyfitz, and Greville.
The French Institute for Demographic Studies is a French research institute specializing in demography and population studies in general.
This article lists current estimates of the world population in history. In summary, estimates for the progression of world population since the Late Middle Ages are in the following ranges:
The middle of the 20th century was marked by a significant and persistent increase in fertility rates in many countries of the world, especially in the Western world. The term baby boom is often used to refer to this particular boom, generally considered to have started immediately after World War II, although some demographers place it earlier or during the war. This terminology led to those born during this baby boom being nicknamed the baby boomer generation.
The birthday effect is a statistical phenomenon where an individual's likelihood of death appears to increase on or close to their birthday. The birthday effect has been seen in studies of general populations in England and Wales, Switzerland, Ukraine, and the United States, as well as in smaller populations such as Major League Baseball players. Studies do not consistently show this effect; some studies find that men's and women's mortality rates diverge in the run-up to the birthday, while others find no significant gender effect. Suggested mechanisms for the effect include alcohol consumption, psychological stress relating to the birthday, increased suicide risk, terminally ill patients attempting to hold on until their birthday, an increased mortality salience, or a physiological cycle that causes the body to weaken annually. It has also been suggested that it may be a statistical artifact, perhaps as a result of anomalies in reporting, but the birthday effect has also been seen in studies that control for known reporting anomalies.
In anthropology and demography, the human sex ratio is an index written as the ratio of males to females in a population. Like most sexual species, the sex ratio in humans is close to 1:1. In humans, the natural ratio at birth between males and females is slightly biased towards the male sex: it is estimated to be about 1.05 or 1.06 or within a narrow range from 1.03 to 1.06 males per female.
Niels Keiding was a renowned and influential Danish Biostatistician.
