Abstract: A system and methods are disclosed for enabling a purchaser to make informed, customized purchasing decisions about a plurality of suppliers based on environmental impact data entered by the suppliers. The system enables a supplier to input data about the environmental impact of production process. The system enables the supplier to grant access permission to the input data to one or more purchasers. The system applies a normalization curve to normalize the data. The system also enables the supplier to identify up-stream production entities. The system enables the up-stream production entities to anonymously input environmental impact data. A purchaser enters a plurality of weight values indicating the relative importance of the environmental impact factors. Based on the inputted data by the suppliers and the up-stream production entities, and based on the weight values, the system provides at least one customized supplier environmental impact score to the purchaser.