A genealogy provides an account of the ancestors and descendants of a person or family. It describes the relationships among a group of individuals descended from common ancestors or a founding couple. The primary pieces of information contained within genealogies are individual-level demographic events, including the dates (and often places) of birth, marriage (s), and death. Each of these events links an individual to other persons: A birth ties an individual to parents and siblings; a marriage, to a spouse, in-laws, and children; and a death, to surviving family members. Other information may also be available in a genealogy, although the quality, coverage, and type of information vary.
The descendants of a founding couple are all related, and this web of kinship is generally referred to as a pedigree. The genetic connection between an ancestor and a descendant is often termed a lineage; tracing ancestors through the maternal side of the family is matrilineal, and similarly, through the paternal side, patrilineal. While genealogies contain information about the nature of the blood relationship between any two individuals, they may also contain information on persons and families living in the same place during the same historical period but who are unrelated.
Because the same data are recorded for each individual, genealogies can be used to answer questions related to entire kinship networks, including questions about demographic conditions and change. Topics examined using genealogical data include temporal patterns in fertility, widow and widower survival, longevity, consanguinity, and genetic variation.
Historical and Family Data
Some genealogies span many generations. This historical depth provides opportunities to examine how broader social changes affect family-level patterns in fertility, migration, and mortality. For some historical periods, genealogies are the principal source of data about the prevailing demographic conditions, although the information they provide is unlikely to be representative of the population at large. In other cases, genealogies provide an important supplement to official records of births, marriages, and deaths. Unlike those records, which are collected and maintained at the individual level, genealogical data are organized around nuclear families and extended pedigrees. Such data may allow analysts to estimate patterns of fertility (e.g., age at first birth, parity, birth intervals, age at last birth), marriage (e.g., number and outcome of marriages, polygamy, consanguineous marriages), and mortality (e.g., infant mortality, maternal mortality, widowhood and surviving spouse mortality, longevity). Genealogies also hold data on predictors of these outcomes, such as gender, age, and places and dates of important demographic transitions. In some genealogies, information on religion and social standing are also available. Standard demographic analysis can then be substantially improved and expanded to incorporate explanatory variables associated with characteristics of offspring, siblings and parents.
Genealogies offer major opportunities for the study of kinship and its changes over time. Genealogies contain a record of the life course of an individual and the additions and losses to his or her kinship network. From a genealogy, it is possible to discern the family circumstances into which a person is born, the survival of siblings, the timing of the person's marriage and subsequent fertility patterns, the presence and location of in-laws, and the survival of his or her parents. Rather than relying on a static view of family life and structure at an arbitrary age or point in history, genealogical data allow the study of these transitions, their causes and consequences, and their patterning over large stretches of individual and historical time. Assembled as a linked set of life histories, the resulting data can be analyzed using statistical techniques that allow for changes both in outcomes and explanatory factors (e.g., time series analysis, survival models with time-dependent covariates).
Assessing Demographic Behavior within Families and Pedigrees
Genealogies do not generally contain the extensive number of covariates often found in large national demographic surveys. However, they do permit examination of the effects of observable predictors on key demographic outcomes while controlling for a wide range of family characteristics that are unobservable. For example, in a study of infant mortality, it might be of interest to know whether a child's birth order affects its chances of surviving the first year of life. Given that the mortality risks for one child are related to the mortality risks of its siblings (for reasons that are not observable to the demographer), one can exploit the fact that siblings share similar environmental and genetic characteristics. Analytical techniques that take this statistical dependency into account include the estimation of robust standard errors and fixed-and random-effects models.
Genealogies and Studies of Communities
Some genealogies are geographically based so that demographic events affecting a set of pedigrees occur in a defined place. This strategy has been used in places where parish registers and reconstructed family histories of entire villages make it possible to develop a genealogical database. Genealogies constrained by geography, while more limited in their scope, provide an opportunity to study a complete (and often relatively closed) social system. Focusing on a particular region or community during key historical periods can provide insights into the demography of families that would not otherwise be possible.
Demographers are often faced with data that are subject to various forms of non-random selection and the biases that they engender. For example, a study of maternal mortality requires that a woman live to reproductive age, have a partner or be married, and bear children before maternal mortality can be examined. Because many genealogies are a record of extinct cohorts where a person's life and its events are depicted from birth to death, it is possible to observe and understand who has been selected out of the sub-population of interest and to make assessments of any selection biases that omissions may present.
Example: Utah Population Database
A summary account of the large number of genealogies that may be of interest to demographers was given by Natalia Gavrilova and Leonid Gavrilov (specialists in the biodemography of aging) in their 1997 study. What follows is a brief description of one of the world's largest and most comprehensive computerized genealogies: that contained within the Utah Population Database (UPDB). In the 1970s, approximately 170,000 Utah nuclear families were selected from the archives held in the Utah Family History Library, each with at least one member having had a vital event (birth, marriage, death) on the Mormon Pioneer Trail or in Utah. These families have been linked across generations; in some instances, the records span seven generations. The UPDB holds data on migrants to Utah and their Utah descendants (not only Mormons, that is, members of the Church of Jesus Christ of Latter-day Saints) that number more than 1.3 million individuals born from the early 1800s to the mid-1900s and that are linked into multi-generation pedigrees. The UPDB is an active genealogy: New families and their members are continually being added as the UPDB is linked to other sources of data, including birth and death certificates. Additional information on these families comes from sources such as drivers' license records and the Utah Cancer Registry. With these additions, the database represents over 6 million individuals. Studies using the UPDB can examine the availability of kin, intergenerational transmission of demographic outcomes (e.g., age at first birth, children born), and familial clustering of specific conditions (e.g., extreme longevity, cancer mortality). These latter lines of inquiry are also of interest to anthropologists, biologists, and geneticists.
Bean, Lee L., Geraldine P. Mineau, and Douglas Anderton. 1990. Fertility Change on the American Frontier: Adaptation and Innovation. Berkeley: University of California Press.
Bean, Lee L., Geraldine P. Mineau, and Ken R. Smith. 1999. "The Longevity of Married Couples." In Nearly Everything Imaginable: The Everyday Life of Utah's Mormon Pioneers, ed. Ronald W. Walker and Doris R. Dant. Provo, UT: Brigham Young University Press.
Dyke, Bennett, and Warren T. Morrill ed. 1980. Genealogical Demography. New York: Academic Press.
Jorde, Lynn B. 2001. "Consanguinity and Prereproductive Mortality in the Utah Mormon Population." Human Heredity 52: 61–5.
Kerber, Richard A., Elizabeth O'Brien, Ken R. Smith, and Richard M. Cawthon. 2001. "Familial Excess Longevity in Utah Genealogies." Journal of Gerontology: Biological Sciences 56: B130–9.
Knodel, John. 1970. "Two and a Half Centuries of Demographic History in a Bavarian Village." Population Studies 24: 353–376.
Mineau, Geraldine P., Ken R. Smith, and Lee L. Bean. 2002. "Historical Trends of Survival among Widows and Widowers." Social Science and Medicine 54: 245–254.
Willigan, Dennis J., and Katherine A Lynch. 1982. Sources and Methods of Historical Demography. New York: Academic Press.
Gavrilova, Natalia, and Leonid Gavrilov. 1999. "Data Resources for Biodemographic Studies on Familial Clustering of Human Longevity." Demographic Research. <http://www.demographicresearch.org/Volumes/Vol1/4>.
Utah Population Database. 2003. <http://www.hci.utah.edu/groups/ppr>.
Ken R. Smith
Geraldine P. Mineau
"Genealogical Records." Encyclopedia of Population. . Encyclopedia.com. (September 19, 2018). http://www.encyclopedia.com/social-sciences/encyclopedias-almanacs-transcripts-and-maps/genealogical-records
"Genealogical Records." Encyclopedia of Population. . Retrieved September 19, 2018 from Encyclopedia.com: http://www.encyclopedia.com/social-sciences/encyclopedias-almanacs-transcripts-and-maps/genealogical-records