Population Research and Policy Review 18: 491–505, 1999.
© 1999 Kluwer Academic Publishers. Printed in the Netherlands.
Unveiling the demographic ‘action’ in class-action lawsuits:
Two instructional cases
PETER A. MORRISON
RAND, Santa Monica, California, USA
Abstract. Population turnover, cohort survival, and intercohort transmission of effects are
concepts widely applicable beyond the customary domains of demographic analysis. One such
application involves a cohort of victims referenced in time and place by a common harm for
which legal redress is sought through a class-action lawsuit. Two instructional case studies
illustrate applications of demographic reasoning and data to certain generic questions such
litigation may pose: How many claimants will remain by some future date? How prevalent will
they then be in the population? How feasible will it be to redress the harm years later? These
cases illustrate the use of familiar demographic concepts and simple demographic reasoning
to draw legally relevant conclusions from available data. Speciﬁc instructional applications
include: accounting for demographic factors that deplete the original class over time and
dilute its surviving members among residents at the referenced place; integrating the use of
administrative record, census, and vital statistics data; and devising approximate estimates of
turnover within local populations. Training is broadly suited to assignments aimed at apply-
ing common-sense demographic reasoning to devise nonstandard solutions to measurement
Keywords: Applied demography, Class action, Law, Teaching
Population turnover, cohort survival, and intercohort transmission of effects
are familiar demographic concepts widely applicable beyond the custom-
ary domains of demographic analysis. This article offers an excursion, for
instructional purposes, into one such application: the class-action lawsuit.
Substantively it introduces the reader to the legal context of such lawsuits
and certain derivative questions which can be addressed demographically.
Technically it illustrates the use of common-sense demographic reasoning
to answer those questions and draw legally relevant conclusions.
Class-action lawsuits typically involve large groups of victims with in-
juries linked to some cause. They bring together small claims impractical
to litigate individually. By aggregating small claims, class actions lower lit-
igation costs and enhance legal resources brought to bear. A claim is ﬁled
by or against parties acting as representatives for similarly situated persons.