Editing Demography (section)

=== Indirect methods ===
Indirect methods of collecting data are required in countries and periods where full data are not available, such as is the case in much of the developing world, and most of [[historical demography]]. One of these techniques in contemporary demography is the sister method, where survey researchers ask women how many of their sisters have died or had children and at what age. With these surveys, researchers can then indirectly estimate birth or death rates for the entire population. Other indirect methods in contemporary demography include asking people about siblings, parents, and children. Other indirect methods are necessary in historical demography.{{citation needed|date=May 2023}}

There are a variety of demographic methods for modelling population processes. They include models of mortality (including the [[life table]], [[Gompertz curve|Gompertz models]], [[Proportional hazards models|hazards models]], [[Proportional hazards models|Cox proportional hazards models]], [[Decrement table|multiple decrement life tables]], Brass relational logits), [[fertility]] (Hermes model, [[Ansley J. Coale|Coale]]-Trussell models, [[parity progression ratios]]), marriage (Singulate Mean at Marriage, Page model), disability ([[Sullivan's method]], multistate life tables), [[population projections]] ([[Lee–Carter model|Lee-Carter model]], the [[Leslie matrix|Leslie Matrix]]), and [[population momentum]] ([[Nathan Keyfitz|Keyfitz]]).

The United Kingdom has a series of four national birth cohort studies, the first three spaced apart by 12 years: the [[National Survey of Health & Development|1946 National Survey of Health and Development]], the 1958 [[National Child Development Study]],<ref>{{cite journal |author=Power C and Elliott J |title=Cohort profile: 1958 British Cohort Study |journal=International Journal of Epidemiology |volume=35 |issue=1 |pages=34–41 |year=2006 |pmid=16155052 |doi=10.1093/ije/dyi183|doi-access=free }}</ref> the [[1970 British Cohort Study]],<ref>{{cite journal |author=Elliott J and Shepherd P|title=Cohort profile: 1970 British Birth Cohort (BCS70)|journal=International Journal of Epidemiology |volume=35 |issue=4 |pages=836–43|year=2006 |doi=10.1093/ije/dyl174 |pmid=16931528|doi-access=free }}</ref> and the [[Millennium Cohort Study]], begun much more recently in 2000. These have followed the lives of samples of people (typically beginning with around 17,000 in each study) for many years, and are still continuing. As the samples have been drawn in a nationally representative way, inferences can be drawn from these studies about the differences between four distinct generations of British people in terms of their health, education, attitudes, childbearing and employment patterns.<ref>The last three are run by the [http://www.cls.ioe.ac.uk Centre for Longitudinal Studies] {{Webarchive|url=https://web.archive.org/web/20181028075855/http://www.cls.ioe.ac.uk/ |date=28 October 2018 }}</ref>

Indirect standardization is used when a population is small enough that the number of events (births, deaths, etc.) are also small. In this case, methods must be used to produce a standardized [[mortality rate]] (SMR) or standardized incidence rate (SIR).<ref>{{cite web |url=http://www.geo.hunter.cuny.edu/~imiyares/standard.htm |title=Direct and Indirect Standardization of Mortality Rates |accessdate=26 March 2016 |url-status=dead |archiveurl=https://web.archive.org/web/20160403114527/http://www.geo.hunter.cuny.edu/~imiyares/standard.htm |archivedate=3 April 2016 }}</ref><ref>{{Cite web |url=http://www.cid.harvard.edu/cidstudents/thesis_prize/thesis_2001/appendix_a.pdf |title=examples of standardization |access-date=16 October 2022 |archive-date=7 July 2017 |archive-url=https://web.archive.org/web/20170707210711/http://www.cid.harvard.edu/cidstudents/thesis_prize/thesis_2001/appendix_a.pdf |url-status=live }}</ref>