- Hub index = Accessibility x Centrality
- The Airports Council International (ACI) also conducts annual airport competitiveness assessment based on the same basic concept (accessibility/centrality).
- Accessibility: Factor indicating how well the airport is connected to other airports (number of international departures, a thousand flights)
- Centrality: Factors indicating how many transits take place centered on the corresponding airport (number of transit passengers per 72 hours, one million)
Since the hub index is calculated as raw data, it may be different from the multiplication of accessibility and centrality index which is expressed to the second decimal place.