Qual Quant (2015) 49:1549–1551
Qualitative and quantitative methods in complex
Marco Fattore · Rosanna Grassi
Published online: 26 July 2014
© Springer Science+Business Media Dordrecht 2014
Several phenomena of real world and many concrete problems, in different contexts, can be
addressed through the concept of “complex system”, i.e. a multiplicity of agents interacting
both among themselves and with the environment they are embedded in. This is conﬁrmed by
the continuously growing interest showed by the scientiﬁc community towards “complexity”
and its applications to real issues. Moreover, in recent years the toolbox of both qualitative and
quantitative models designed to describe and better understand complex systems has found
various ﬁelds of application, particularly within the socio-economic area. Network models,
stochastic and dynamics systems, social network analysis, multivariate statistics, inference
and stochastic processes, fuzzy theory, relational calculus, partial order theory, multi-criteria
decision methods… all of these tools ﬁnd their place in the study of real complex systems. In
this Special Issue, mainly dedicated to complex socio-economic, ﬁnancial and environmental
problems, you will ﬁnd an application for most of them.
Most papers in this issue were originally presented at the 6th International Workshop on
Dynamics of Social and Economical Systems held in Ushuaia, Tierra del Fuego, Argentina
organized by Asociacion Dyses (Argentina, http://www.dyses.org.ar), Group of Studies in
Multifractal and Complexity (GEMC) of Universidad Nac. de Gral. Sarmiento, Laboratorio
de Sistemas Complejos, Facultad de Ingenieria-UBA (Argentina)(http://laboratorios.ﬁ.uba.
ar/lsc/), and GECSI, Grupo de Estudio de la Complejidad en la Sociedad de la Información,
Facultad de Ciencias Jurídicas y Sociales Universidad Nacional de La Plata (Argentina).
Many papers in this volume apply complex network theory to economic or ﬁnancial ﬁelds.
L. Catalano and A. Figliola in “Analysis of the nonlinear relationship between com-
modity prices in the last two decades” describe the construction of a network useful for
the study of the correlations among the price indexes of different commodities, obtained by
using the Multi-fractal Cross-Correlation method. They consider different networks, where
nodes represent commodity groups and links represent cross-correlations, and study their
evolution from 1991 to 2012.
M. Fattore · R. Grassi (
University of Milano Bicocca, Milano, Italy