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, socio-institutional power and communicative-cultural power of a state.
Material Capacities Index (MCI)
Material Capacities Index (MCI) was first published in the book Potencias medias y potencias regionales en el sistema político internacional de Guerra Fría y Posguerra Fría. In an improvement of this, all the original indicators remained and Total reserves (includes gold, current US $) was added as a new indicator. The MCI is a composite index that seeks to reflect more broadly the economic and military power of states from considering six variables:
- national production,
- total area,
- military expenditure,
- spending on research and development,
- international commerce,
- foreign-exchange reserves.
MCI results for the rest of the world have been published for the first time in Poder, estructura y hegemonía: pautas para el estudio de la gobernanza internacional. Volumen I: Índice de Poder Mundial, work that summarizes annual results from 1975 to 2013.
Semi-Material Capacities Index (SMCI)
Semi-Material Capacities Index was also first published in the book Potencias medias y potencias regionales en el sistema político internacional de Guerra Fría y Posguerra Fría, but with the name of Intangible Capacities Index. In a review of it, its name was changed to Semi-Material Capacities Index (SMCI) because it was not intended measure communicative-cultural or immaterial power, but the dimension that corresponds to the socio-institutional power and it is theoretically placed between power material and immaterial power: “semi-material” power.
To maintain methodological congruence with the MCI, the Human Development Index (which was originally considered to weigh the semi-material capacities) was removed because it is a composite index. Instead, they were embedded one pair of simple indexes. Thus, SMCI is a composite index that seeks to refer the socio-institutional power of a State from considering six variables:
- national production per capita,
- per capita consumption,
- per capita energy consumption,
- spending on education,
- health spending.
SMCI results for the rest of the world are also available in Poder, estructura y hegemonía: pautas para el estudio de la gobernanza internacional. Volumen I: Índice de Poder Mundial, from 1975 to 2013.
Immaterial Capacities Index (IMCI)
Immaterial Capacities Index (IMCI) represents the first attempt to measure the communicative-cultural power or what has been expressed by others as soft power or symbolic power. IMCI is another composite index, made from six variables that are intended to reflect more broadly cultural communicative power of a State from:
- government expenditure,
- international tourism receipts,
- official development assistance per capita,
- number of telephone lines,
- number of articles in scientific and technical journals,
- stock of international migrants.
IMCI results for other countries are available on Poder, estructura y hegemonía: pautas para el estudio de la gobernanza internacional. Volumen I: Índice de Poder Mundial for the period 1975-2013.