(92)When assessing the best price-quality ratio contracting authorities should determine the economic and qualitative criteria linked to the subject-matter of the contract that they will use for that purpose. Those criteria should thus allow for a comparative assessment of the level of performance offered by each tender in the light of the subject-matter of the contract, as defined in the technical specifications. In the context of the best price-quality ratio, a non-exhaustive list of possible award criteria which include environmental and social aspects is set out in this Directive. Contracting authorities should be encouraged to choose award criteria that allow them to obtain high-quality works, supplies and services that are optimally suited to their needs. The chosen award criteria should not confer an unrestricted freedom of choice on the contracting authority and they should ensure the possibility of effective and fair competition and be accompanied by arrangements that allow the information provided by the tenderers to be effectively verified. To identify the most economically advantageous tender, the contract award decision should not be based on non-cost criteria only. Qualitative criteria should therefore be accompanied by a cost criterion that could, at the choice of the contracting authority, be either the price or a cost-effectiveness approach such as life-cycle costing. However, the award criteria should not affect the application of national provisions determining the remuneration of certain services or setting out fixed prices for certain supplies.