Event history analysis of groups. Initial results from an on-going research project
Éva Leliévre, Catherine Bonvalet, Xavier Bry
The event history approach, which has led to a reformulation of the bases of demographic methodology in terms of analysis of complex stochastic processes (Courgeau and Lelièvre, 1989; 1996), is applied using individual longitudinal data. Ideally, however, each individual itinerary would be situated in as broad a context as possible, and the analysis of individual demographic processes would take account of the close or competing events affecting the individual's entourage. In event history modelling, a shift from the individual to their entourage, for both data collection and analysis, implies a reconsideration of the choice of entities for longitudinal monitoring. A compromise must be reached between conceptual operationality and analytical consistency, in terms of both theory and models: this article presents the formal developments, then the more applied results from this on-going research.
INED, Population no. 4, 1997 - page 803
Multi-level analysis in the social sciences
Daniel Courgeau, Brigitte Baccaïni
The multi-level approach can be used to study human behaviour taking into account not only individual characteristics but also the fact that these individuals belong to larger geographical units such as communes and regions. This article gives a detailed critical presentation of the aims and formulations of these models. Attention ranges from the most basic models, which introduce the many different levels in the form of individual and aggregated characteristics, to more complex models which operate with the random characteristics specific to each level, and culminates with multi-level event history models. The article concludes with a more general epistemological reflection on the contribution of these models.
INED, Population no. 4, 1997 - page 831
Textual statistics. An exploratory tool for the social sciences
France Guérin-Pace
The value of textual statistics is now widely acknowledged in many branches of the social sciences, reflecting the fact that there are few fields of research in which the text is not a major element for analysis.
The statistical processing may be of responses to open questions, interviews, texts and even individual itineraries. The procedures are numerous and can be adapted to different kinds of material. The aim in the present article is to give a broad overview of the various applications of these methods, ranging from the most traditional to the most recent, and focusing on both the methodology used and the results obtained.
INED, Population no. 4, 1997 - page 865
Microsimulation method for population projections
Evert Van Imhoff, Wendy Post
The microsimulation employed in this article differs from traditional macrosimulation in using a sample rather than the total population, in operating at the level of individual data rather than aggregated data, and in being based on repeated random experiments rather than average numbers. Here are presented the circumstances in which microsimulation can be of greater value than the more conventional methods. It is particularly relevant when the results of the process being studied are complex whereas the forces driving it are simple.
A particular problem in microsimulation results from the fact that the projections are subject to random variation. Various sources of random variations are examined but the most important is the one we refer to as specification randomness: the more explanatory variables are included in the model, the greater the degree of random variation affecting the output of the model. After a brief survey of the microsimulation models which exist in demography, a number of the essential characteristics of microsimulation are illustrated using the KINSIM model for projecting the future size and structure of kinship networks.
INED, Population no. 4, 1997 - page 889
Non-linear demographic models and chaotic demo-dynamics
Didier Blanchet
The development of non linear models is undoubtedly a promising field for demographic modelling (Feichtinger, 1993). Linear models derived from stable population theory still remain a basic reference, but it is clear that non linear models offer much more possibilities to account for actual demographic or demoeconomic dynamics. On the other hand, there is one aspect of non linear models which has been probably overemphasized over the last years, which is their ability to generate chaotic dynamics. Up to now, models which have been proposed have some difficulties in deriving such a behavior from plausible assumptions concerning demographic behavior or demo-economic relationships. We illustrate this point of view by discussing two examples, borrowed respectively from Day (1984) and Prskawetz/Feichtinger (1995). Research on this topic can go on, but should pay a particular attention to the realism of assumptions used to build these models.
INED, Population no. 4, 1997 - page 933
Games, equilibria and population regulation under viability constraints
An interpretation of the work of the anthropologist Fredrik Barth
Noël Bonneuil
The anthropologist Fredrik Barth has drawn on the mathematical notions of equilibrium in dynamic systems theory and in game theory to show how social forms are generated by individual interactions.
In this article, however, it is suggested that what is involved is less equilibria than viability. The main aim of Basseri nomads is to be able to stay on their lands, while for Norwegian fishermen it is to find fish. To achieve this result, each actor has a certain freedom of action that they must use in the right way at the right time. In an environment characterized by uncertainty and constraints, the individuals can operate the controls through which the systems can perpetuate themselves.
The exact future of a system cannot be predicted, but it is possible to identify the largest set of states from which there is at least one possibility of remaining within the constraints and thus of surviving. It is the law of regulation which provides the set of viable controls for each state.
Other applications of viability theory in demography are presented in appendices. These concern fluctuations in fertility, the Malthus-Boserup dynamic between population and resources, the relationship between predator-prey populations, and the research for the population paths which could have produced the present genetic heterogeneity.
INED, Population no. 4, 1997 - page 947
The spatial diffusion of contraception in Great-Britain and the origins of the fertility transition
Jean-Pierre Bocquet-Appel, Lucienne Jakobi
Contraception can be diffused according to several modes: vertical (social), horizontal (geographically) or both (oblique). Most authors subscribing to a view of a diffusion at the start of the European fertility transition use the term in the sense of a vertical diffusion. This article reexamines the nature of the diffusion, by testing the hypothesis of a horizontal diffusion at the onset of the transition. The data used are the rate of variation in the Ig fertility index and 8 socio-demographic variables representing secularization, illiteracy and social scale in 78 counties of Great Britain in the periods 1861-1871, 1871-1881, 1881-1891, 1891-1901. A two-stage approach is used: probabilistic, by a test of the time-space clusterings of the localities just beginning the transition; graphical, by a representation of this indicator cumulated on a map. It is shown that only a process of geographical diffusion can generate such a representation with a diffusion velocity of 14.6, 26.1, 42.4 and 34.9 km/year for each period. As in France, there is no coincidence between the political, economic and cultural centre of Great Britain, represented by London, and the point of origin of the diffusion of contraception.
INED, Population no. 4, 1997 - page 977
The fractal approach. A new tool for the spatial analysis of urban agglomerations
Pierre Frankhauser
Tractal geometry is a new approach for the study of spatial distributions. The basic model is a law of hierarchical distribution corresponding to Pareto's law which is familiar to urban geographers and demographers. The methods of fractal analysis can be used to study the spatial organization of human activities across scales. The regularities and the discontinuities in the distributions can then be identified. These discontinuities can be spatially situated. Applying this concept to urbanized areas has shown that districts can be defined and classified according to their scaling relations, thereby allowing development of a typology of locational patterns. This observation reveals the existence of a principle of self-similarity in land-use patterns. An examination of time series shows that despite the apparent fragmentation of these urban tissues, urbanization is often accompanied by structured development.
Subsequent research will need to employ complementary morphological measures, such as measures of space filling and of population distribution, which could be used to validate the simulation models based on fractal geometry.
INED, Population no. 4, 1997 - page 1005
