The Modified Diagonalization Method for Analysing Clusters within Economies

In this paper a modification of the diagonalization method, originally put forward by Hoen (2002), is suggested which is aimed at uncovering clusters of sectors within an input-output framework. Our interest in this subject was largely motivated by the fact that the preceding method appears to be incapable of providing us with an accurate representation of the real cluster structure that exists in an economy, as a consequence of missing the position at which a given inter-sectoral flow stands in the hierarchy of the purchasing industry and the supplying industry. By making a distinction between an internal and external relationship, when it comes up at the moment of deciding whether each pair of industries is categorized as belonging to the same or different clusters, the proposed alternative, which will be referred to as the modified diagonalization method, seems to be superior to its predecessor. Such a conclusion is supported by the results of comparison of the relative performance of the rival methods (i.e. the original and modified diagonalization method) which show, among other things, that the average value of flows between industries grouped into clusters is higher in the case of the proposed method.