The Global Hegemony Index (GHI) has progressively expanded its scope of data collection over the 1991–2023 period, culminating in 31 indicators by the 2020–2023 phase. These indicators are drawn from both original research and a wide range of publicly available national and international data sources. We assigned a set of weightings to the components of the GHI to reflect their relative importance in the exercise of state power. These weightings are informed by the collective judgment of the experts involved in this project and grounded in relevant academic literature. They take into consideration the varying scales of capacity and influence among G20 members, including the European Union.

The GHI was normalized by designating the United States' score in 2003—identified in our analysis as the apex of American national power—as the fixed peak value of 100. All other index scores across countries and years were proportionally rescaled to this benchmark, ensuring consistent cross-national and longitudinal comparability.