International Journal on Criminology Volume 1, Number 1, Fall 2013 | Page 46

Demographic Analysis of the Penal System
real “micro” second category alternative, which clearly benefits the offender, might
become virtual at the “macro” level. 16
7. Foretelling the future?
POPULATION PERSPECTIVE: Similar terms also used are projection or forecast. 17
Projection refers to calculations regarding a population's future evolution based on certain
hypotheses that are not necessarily plausible. This is generally the case when calculating
the amount of time required for a population to double. We simply look at the
consequences a change may have on the rate of relative annual constant increase over a
period of time.
When the hypotheses are more or less plausible, we then speak of perspective. The
term “forecast” is only used when the hypotheses upon which they are based appear very
probable.
In addition, there are distinctions between descriptive and explanatory perspective
models. At the beginning of the 1980s (2), Marie Danièle Barré and I used a very simple
descriptive model to study the prison population, using only time to explain changes in
trends. This model is based on the linear extrapolation of past tendencies (chronological
series) and the consideration of the prison population's seasonal variations (stocks on the
first day of the month). For instance, using the prison population on December 31, 2005,
this technique makes it possible to estimate the number of individuals in prison on the
first day of each month in 2006 and 2007 (unless there are “disruptive phenomena” not
taken into account in the calculation). Thus on that date, we might suppose, but without
any certainty, that there will be an amnesty after the presidential election in May 2007; it
is simply a tradition of the Republic and nothing requires Parliament to make such a law.
This is the first uncertainty. The second uncertainty is that, if there is a vote, this law may
be more or less lenient and may therefore have a greater or lesser effect on the prison
population. A third uncertainty is whether the law will be combined with a collective
pardon. While these calculations cannot claim to “foretell” and require frequent
adjustments, they do show the numerical consequences of a simple hypothesis: if changes
continue according to the trend of recent years, where are we headed? They are also a
good economic tool, allowing calculations to be made for budgetary purposes, monthly
statistics to be put into perspective (taking seasonal variations and so on into account),
and the effects of an amnesty or collective pardon to be measured. Nonetheless, the
model we introduced in 1979 has since been taken up for the study of correctional
administration and seems to have been of some use.
Explanatory models are much more ambitious. 18 They can be either mechanistic or
theoretical. In the first case, the formation process of the prison population is broken
down into its different stages: crime submitted to the court, crime prosecuted, crime
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16 Pierre V. Tournier, “Real Alternatives Versus Virtual Alternatives: On the Theory of Net-
Widening Applied to Electronic Monitoring in France,” in Will Electronic Monitoring Have a
Future in Europe? eds M. Mayer, R. Haverkamp, and R. Lévy (Freiburg: Max Planck Institute,
2003), 177-186.
17 Louis Henry. Dictionnaire démographique multilingue, volume français (Liège: Ordinal Editions,
1981).
18 Marie Danièle Barré. “Résistible progression des effectifs de la population carcérale en France?
Réflexion sur les projections.” Paper presented at the 8 th National Demographic Colloquium,
Grenoble, France, 1987.
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