This article analyzes the methods of selecting the most economically advantageous tender in public procurement. It has two objectives. First, it assesses the properties of the relative bid evaluation formulas used in practice in the criteria for selecting the bids. Through examples, it shows that these bid evaluation formulas turn out to be rather arbitrary, manipulable, and do not reveal the preferences of the public purchasers. The article then presents steps for constructing a scoring rule that puts bidders in competition in a transparent way. This involves choosing for each criterion a bid evaluation formula and a weighting that reflect the preferences of the public purchaser.