This book aims to show how the multilevel approach successfully
overcomes the divisions that emerged during the rise of the social
sciences-- specifically, here, demography and statistics--from the
seventeenth century to the present. We begin by examining how the
approach connects different branches of the social sciences that
conducted their observation and analysis at different levels or
addressed different aspects of human complexity. Next, we describe in
greater detail the statistical methods and techniques that it can use to
simultaneously identify and measure the effects of the different levels
examined on the characteristics studied. To introduce this work, we
first provide an overview of the goal of social sciences, before
discussing the various levels of aggregation at which they can operate.
Social sciences start from the observation of a real-life experience and
then seek to structure it according to different fields, which
constitute the specific objects of study for each science. As a rule,
these objects are defined independently of the scale and levels of
aggregation that can be chosen to observe them. For example, the object
of demography is the quantitative study of human populations, their
variations, and their status, without specifying whether the level
chosen is the individual, the family, the population of a town, or that
of a country. Likewise, economics studies the production, distribution,
and consumption of wealth, without specifying if the analysis is of an
individual, a market, a firm or a nation.