Abstract: A data processing method for an environmental certification program is provided which defines a plurality of predefined criteria which must be met by a participant in the program in order to be provided with a privilege of providing a certification mark for use on goods and in advertising materials of the participant. The data processing method tracks the compliance by the participant with the environmental certification program, and further evaluates the continued certification of a participant in the program. Preferably, continued certification requires achieving additional predefined criteria while maintaining the predefined criteria which led to initial certification. Moreover, compliance with the predefined criteria is preferably ensured with periodic on-site verification.