Quality & Quantity 33: 219–227, 1999.
© 1999 Kluwer Academic Publishers. Printed in the Netherlands.
Longitudinal Research and the Analysis of Social
Coordinating Editor’s Introduction
Università degli Studi di Padova, Dipartimento di Sociologia, via S. Canziano, 8, 35122 Padova,
The aim of this special issue of Quality and Quantity is to collect the contributions
to the International Workshop ‘Longitudinal Analysis: A Bridge between Quanti-
tative and Qualitative Social Research’, held at the University of Padua between
14–16 May 1998. All chapters were originally presented as papers at the above
The Workshop had four main purposes.
(1) To explain what longitudinal data analysis is and to discuss why introducing a
temporal element can increase the explanatory power of empirical analysis;
(2) To offer an overview of some of the methods which can be used to analyse
(3) To provide information about some of the existing longitudinal data sets;
(4) To discuss and compare some of the empirical evidences which has emerged
from ‘qualitative’ and ‘quantitative’ longitudinal research.
More speciﬁcally, the Workshop aimed to identify both the possibilities offered
by and the problems inherent in longitudinal data. If, on the one hand, such data
can, potentially, provide fuller information about individual behaviour, on the other
hand, it is also true that the use of such data poses crucial theoretical and method-
ological problems. This is one of the reasons why there is still a gap between the
growing availability of longitudinal data and everyday practices in Social Science
research, which is still mostly conﬁned to cross-sectional analysis.
However, the use of longitudinal data (both retrospective and prospective) can
ensure a more complete approach to social empirical research. With these data,
social investigators have powerful instruments to get to the heart of many processes
of social change.
Longitudinal data’s heuristic potential is indeed immense. Such data not only
permit analysis of duration, but also facilitate the measurement of differences, or
changes, in a variable from one period to another and the testing of the direction
(positive or negative and from Y to X or from X to Y) and magnitude of causal
relationships (Menard, 1991: 5). Therefore, our insight into processes of social