Demography is the study of the particulars of the composition of a human population through the use of statistics.  Statistics can define and illustrate the changing structure of human population by tracking such things as births, deaths, income level, education level or the incidence of disease.  By relating these statistics over time we can see the trends and evolution in the human population.

Demography can be further used to breakdown the human population into subsets.


 More detail can be examined for a particular human population that may relate to the question at hand more directly.  In ergonomics these populations become the basis for design and analysis.  Through the use of demography one can determine the needs of a target user population and design or analyze with those specifics in mind.

The filed of anthropometry is simply a very specific demographic function.  It is the statistical representation of human body dimensions for specific population subsets.  While it is possible to develop a data set for the anthropometrics of the entire human population the range would be so wide that it would make most designs inefficient.

Instead a smaller population is measured and used for more relevant design analysis.  Should a target user set be such that multiple anthropometric populations would be the users then those data sets are merged.