The design stage represents one of the most critic steps for product development. Here, a great number of considerations have to be borne in mind, e.g., technical, functional, aesthetic or economic criteria. More recently, the increasing concerns on environmental aspects have added complexity to the process, known as ecodesign. In this respect, a framework to integrate the criteria provided by quantitative environmental indicators has been proposed on the basis of Fuzzy Preference Programming method features and fuzzy logic reasoning. As a result, an integrated Ecodesign Index (EcoInd) is obtained. This idea enables the decision making at process and product level taking into account different indicators at a time. The ecodesign of children's footwear was taken as case study and an ecodesign tool (decision support system) that included the estimation of environmental indicators and their integration was developed. Different models of shoes were analyzed to identify the most environmentally friendly design and to test the tool. In this case, the Ecological Footprint and two Environmental Risk Assessment indicators, namely Hazard Quotient and Cancer Risk, were selected as relevant environmental indicators and they were computed from data provided by a shoes manufacturer. Then, these indicators were integrated in the ecodesign tool and the EcoInd values were appraised for the children's footwear models analyzed. According to these figures, they were ranked as Red Leather>White Leather>White Synthetic>Pink Synthetic, from best to worst. Adherence Factor (mgcm−2) Analytic Hierarchy Process Fuzzy Preference Programming Method Benzylbutylphthalate Mean Body Weight (kg) Center – One Side Gaussian Membership Function Parameter Consistency Index Consistency Ratio Cancer Risk Concentration of a Contaminant in the Shoes (mgkg−1) Contact Time (hday−1) Dermal Absorption Factor Dibutyl Phthalate Di(2-Ethylhexyl) Phthalate Di-Isononyl Phthalate Decision Maker Exposure Dose to the Chemical (mgkg−1 day−1) Ecoquality Function Deployment Ecodesign Index Maximum Ecodesign Index Ecological Footprint (gm2/Pair of Shoes) Ecological Footprint by Subcategory (gm2/Pair of Shoes) Elimination and Choice Expressing Reality Method Energy Productivity by Subcategory (GJha−1 y−1) Environmental Risk Assessment Consumption/Generation of Energy for Each Subcategory r (GJ) A User-Friendly Software [16] for the Development of Multivariable Indices Fuzzy EcoDesign Index [19]. Equivalence Factor (**) Fuzzy Hazardous Waste Index Fuzzy Water Quality Index Generalized Reduced Gradient Result of a Fuzzy Aggregation Method Hazard Quotient Indicates the Corresponding Design to be Evaluated Indicates the Corresponding Environmental Indicator Indicates the Corresponding Ecological Footprint (EF) Category Indicates the Corresponding Kinds of Land (EF) Fuzzy Number Lower Value Life Cycle Assessment Lower Bound of the jth Environmental Indicator (*) Fuzzy Number Center Value Monte Carlo Simulation Multiple Objective Programming Number of Considered Environmental Indicators Natural Productivity (tha−1 y−1) Probability Distribution Function Preference Ranking Organization Method for Enrichment Evaluation Indicates the Corresponding Ecological Footprint (EF) Subcategory Reference Doses for Non-Carcinogenic Effects (mgkg−1 day−1) Consistency Index of a Randomly Generated Reciprocal Matrix Sustainability Assessment by Fuzzy Evaluation Mean Surface Area for Feet (m2) Slope Factors for Carcinogenic Effects (kgdaymg−1) Fuzzy Number Upper Value Upper Bound of the jth Environmental Indicator Visual Basic for Applications Consumption/Generation for Each Subcategory r/Pair of Shoes (t) jth Environmental Indicator (*) Normalized jth Environmental Indicator Parameter of the Aggregation Method Consistency Factor of AHP–FPP Method Standard Deviation – One Side Gaussian Membership Function Parameter Maximum Eigenvalue of AHP Matrix Membership Degree (score) for the jth Environmental Indicator Depends on the Type of Environmental Indicator. Equivalence Factors 2003 [42]. 
A decision support system based on fuzzy reasoning and AHP–FPP for the ecodesign of products: Application to footwear as case study