| Variable | Description | Data Sources |
| GDP | Nominal GDP as measure of economic mass (taken in log form) | World Development Indicators (WDI) |
| GDP per capita |
| World Development Indicators (WDI) |
| Linder | It is the absolute value of the difference in GDP per Capita income included to measure income difference | Authors computation using the GDP per capita variable |
| Bilateral Trade data | Panel bilateral trade data for the 9 strategic agricultural commodities for the period 1998 to 2010 for all African countries and selected Industrial and Emerging Economies | CEPII Gravity Database |
| Area | Area in square km | CEPII GeoDist Database |
| Landlocked | 1 if landlocked, 0 otherwise | CEPII GeoDist Database |
| Bilateral Distance | Distance between the trading partners as developed by [27] is computed based on latitude and longitude of the capital cities. | CEPII GeoDist Database |
| Contiguity | 1 if share common border, =0 otherwise | CEPII GeoDist Database |
| Language | 1 if have common official or primary language | CEPII GeoDist Database |
| Colony | 1 if had common colonizer, =0 otherwise | CEPII GeoDist Database |
| Population | Population size of the trading partners taken in log | World Development Indicators (WDI) |
| | 1 if countries i & j belong to a particular RTA and the year (t) is greater than or equal to the year the agreement was signed, 0 otherwise | Authors’ compilation from different sources |
| | 1 if the importer is an RTA member & the exporter a non-member and the year (t) is greater than or equal to the year the agreement was signed, 0 otherwise | Authors’ compilation from different sources |