WP 3 Projections of the Changing Family Unit and Kinship Structure M Murphy, LSE; E Grundy, LSHTM

WP 3 Projections of the Changing Family Unit and Kinship Structure Objective - to produce projections of the older population by age, sex and kinship status Kinship ties become more important with age, as kin form a major resource in times of need. Having kin is a precondition for kin interaction and support Cumulative lifetime experiences such as total number of partnerships substantially affect interactions with other kin.

WP 3 Projections of the Changing Family Unit and Kinship Structure Main demographic trends of first & second demographic transitions in now-developed societies: Initially fertility declined from about five children per woman in 19th century to 'below-replacement level' today mortality has declined so that life expectancy doubled from 40 to 80 years over 20th Century populations aged so around 20% people now aged 65+ More recently substantial reductions in nuptiality and increases in non-marital cohabitation; divorce & proportion of births outside marriage

WP 3 Projections of the Changing Family Unit and Kinship Structure Kinship distribution is determined solely by the fertility, mortality, nuptiality (inc. divorce and cohabitation) experienced by the population for many decades prior to that time point The contemporary pattern of kinship is also influenced by more recent partnership trends, especially when step-kin are considered Little information available in Britain (or elsewhere) on kinship in large nationally-representative data sources.

Micro-simulation Micro-simulation may be used to estimate and project the numbers and types of kin that people are likely to have under various conditions. We start with known or assumed population of many individuals, and then simulate individual demographic events.

The SOCSIM Model Hammel & Wachter (UC Berkeley) “Monte Carlo” method An initial population of individuals sub-divided by sex and age is fed to the computer, and these individuals age month by month; Some will marry (or cohabit) with each other, give birth, divorce or remarry, and finally they die The occurrence of these events for each person of a given age, sex, marital status etc is determined by random numbers in with probability specified by the user's choice of governing demographic rates (i.e. produces correct averages) Model builds up kinship links for an initial population of unrelated and never-married people to any degree of complexity

Proportion with living natural parents and children WP 3 Projections of the Changing Family Unit and Kinship Structure Proportion with living natural parents and children An example: people with living parents and children, 1950, 2000 & 2050

WP 3 Projections of the Changing Family Unit and Kinship Structure Family unit & kinship structure linkages