These rankings are not official and are based on Inara commanders wishing to participate. The rankings are calculated JUST from the values gained via the 'Import game data' feature to ensure all the data provided is valid and not altered in any manner.
The score for the main ladder is based on Combat, Trade, Exploration, Mercenary and Exobiologist ranks, including their progress (5000 points for each tier) with the addition of points for other activities (bounties, combat bonds, trades, scans, etc.) up to a few thousands of points, to differentiate commanders on high ranks. No credits/assets values are used.
The score for the CQC ladder is based on CQC rank, including its progress (5000 points for each tier) with the addition of points for kills (typically up to few hundreds of points). Unfortunately, it is currently not possible to include Prestige and (numerical) rank. Commanders with 'oddly unrealistic' stats are automatically omitted from the rankings.