World Power Index (WPI) is defined as the numeric expression that expresses the accumulation of national capabilities that a State has to exercise its power in the international system. The WPI is resulting from the addition of 18 indicators, which are
themselves organized through three composite indexes:
- Material Capacities Index (MCI),
- Semi-Material Capacities Index (SMCI),
- Immaterial Capacities Index (IMCI).
The WPI is presented as a quantitative analysis technique, seeks help to overcome the hermeneutics underlying the subjective interpretation of power in international relations. Thus, the WPI contributes to the accurate comparison of national capacities and the study of the international structure.
According to Karl Höhn, “power formulas seek to measure mathematically the power resources of a given set of countries in order to make those countries comparable to one another. A power formula typically consists of quantified power indicators”. In that sense, World Power Index is just a proposal made and used by Mexican scholars to approach the study of the power of states and the analysis of the international structure.
The WPI went through two preliminary tests, which were subject to revision. The first, published in 2008 and named Structural Positioning Indicator (SPI), expressed national power as a combination of material factors (which were set as hard capacities) and intangible factors (identified as soft skills). These sets of factors were processed through a mathematical function that considered both: metric and ordinal variables. Although it proved to be a useful tool to define and explain the roles of some countries in the international system (specifically Mexico and Brazil), the SPI showed certain shortcomings: 1) if included or subtracted from the analysis any State, the “ranks” built the position of countries resulted significantly altered, and thus, all the SPI; 2) not had an exact Human Poverty Index (indispensable for measuring soft capacities) for the vast majority of states included in analysis; 3) was inoperative handle a structural positioning indicator 3639.111 for US and 0.025 for Burundi; 4) it was very difficult to obtain information for a longer time space that would show trends in the medium and long term. After this exercise, it continued rehearsing in the measurement of power. In 2011 was published the second trial as part of the book Potencias medias y potencias regionales en el sistema político internacional de Guerra Fría y Posguerra Fría. The main limitation of this second test resided in their inability to distinguish theoretically and methodologically between immaterial capacities and semi-materials capacities: the dichotomous view of hard power/soft power of Joseph Nye finally prevailed and engage the index (although not theoretical findings about the nature, characteristics and roles of the powers studied). With its diffusion, the Index was subject to various critiques and observations, which that contributed to its improvement. All this led to the third and most comprehensive test of WPI. New World Power Index, published in 2015 as part of Volume I of the work Power, Structure and Hegemony. Vol. I: World Power Index not only considers the three dimensions of national power as ontological and epistemological starting point, but also it presents first results of WPI (and their respective sub-indexes) to more than 160 countries.
The power of a State is relative to the power of the rest of the state actors from the international system. Likewise, an index is a figure which expresses a relative relationship among a data sequence. An indicator is an absolute value, so it does not reflect a correlation with other values; instead, an index -which is constructed from a consideration of the maximum and minimum values- reaches more clearly show this relativity.
However, there is a huge disparity between the maximum and minimum values internationally. To overcome this problem, the WPI submits each of the values to a logarithm with base 10. This process allows approximate the most extreme data, but equally keeping their original values. So, the WPI is formulated on the basis of three sub-indices that relate the economic-military power (Material Capacities Index), socio-institutional power (Semi-Material Capacities Index) and communicative-cultural power (Immaterial Capacities Index) of a state.