Science overlay maps: a new tool for research policy and library management

Ismael Rafols1, Alan L. Porter2 and Loet Leydesdorff3

1 SPRU –Science and Technology Policy Research, University of Sussex, Brighton, BN1 9QE, England; i.rafols@sussex.ac.uk ;

2 Technology Policy and Assessment Center, Georgia Institute of Technology, Atlanta, GA 30332, USA; alan.porter@isye.gatech.edu; and Search Technology, Inc.

3 Amsterdam School of Communication Research (ASCoR), University of Amsterdam, Kloveniersburg 48, 1012 CX Amsterdam, The Netherlands; loet@leydesdorff.net

Abstract We present a novel approach to visually locate bodies of research within the sciences, both at each moment of time and dynamically. This article describes how this approach fits with other efforts to locally and globally map scientific outputs. We then show how these science overlay maps help benchmark, explore collaborations, and track temporal changes, using examples of universities, corporations, funding agencies, and research topics. We address conditions of application, with their advantages, downsides and limitations. Overlay maps especially help investigate the increasing number of scientific developments and organisations that do not fit within traditional disciplinary categories. We make these tools accessible to help researchers explore the ongoing socio-cognitive transformation of science and technology systems.

Keywords: science, map, overlay, classification, interdisciplinary, research, evaluation.

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1. Introduction

Most science and technology institutions have undergone or are undergoing major reforms in their organisation and in their activities in order to respond to changing intellectual environments and increasing societal demands for relevance. As a result, the traditional structures and practices of science, built around disciplines, are being by-passed by organisation in various ways in order to pursue new types of differentiation that react to diverse pressures (such as service to industry needs, translation to policy goals, openness to public scrutiny, etcetera). However, no clear alternative socio-cognitive structure has yet replaced the “old” disciplinary classification. In this fluid context, in which social structure often no longer matches with the dominant cognitive classification in terms of disciplines, it has become increasingly necessary for institutions to understand and make strategic choices about their positions and directions in moving cognitive spaces. “The ship has to be reconstructed while a storm is raging at sea.” (Neurath, 1932/33) The overlay map of science we present here is a technique that intends to be helpful in responding to these needs elaborating on recently developed global maps of science (Leydesdorff & Rafols, 2009).

Although one would expect global maps of science to be highly dependent on the classification of publications, the clustering algorithms, and visualisation techniques used, recent studies comparing maps created using very different methods revealed that, at a coarse level, these maps are surprisingly robust (Klavans & Boyack, 2009; Rafols & Leydesdorff, 2009). This stability allows to ‘overlay’ publications or references produced by a specific organisation or research field against the background of a stable representation of global science and to produce comparisons that are visually attractive, very readable, and potentially useful for science policy-making or research and library management. In this study, we present one such overlay technique and introduce its possible usages by practitioners by providing some demonstrations. For example, one can assess a portfolio at

3 the global level or animate a diffusion pattern of a new field of research. We illustrate the former application with examples from universities, industries and funding agencies, and the latter for an emergent research topic (carbon nanotubes). In appendices we provide the technical information for making these overlays using software available in the public domain.

Our first objective is to introduce the method for making and/or utilising the global maps to prospective users in the wider science policy and research management communities who are not able to follow the developments in scientometrics in detail. Since the paper addresses a wide audience, we shall not discuss technical bibliometric issues, but provide references to further literature. Secondly, we reflect on issues about the validity and reliability of these maps. Thirdly, this study explores the qualitative conditions of application of the maps, proposing examples of meaningful usage and flagging out potential misreadings and misunderstandings.

As classifications, maps can become embedded into working practices and turn into habit, or be taken for granted away from public debate, yet still shaping policy or management decisions that may benefit some gro

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