Loss of a chance in administrative law

For several years, loss of chance has interested administrative judges and legal writing in public law. The former, who have widely developed its area in law of administrative liability, have changed the method of compensation of this instrument, by using the example of private law. The second has tried to identify the justifications of the use of loss of chance by using the uncertainty of prejudice and the one of causal relationship. But the analysis of jurisprudence shows that, despite the diversity of risks justifying the use of loss of chance, this is in keeping with a unique scope which is characterized by causal uncertainty. The variety is to be found elsewhere, at the stage of compensation. According to the selected method - the all or nothing approach or proportional compensation - the face of the loss of chance changes. It sometimes forms a presumption of causation, sometimes a prejudice, and so overcomes the causal uncertainty in two different ways. The current hesitations of administrative judges prove that it is difficult to choose between one or the other of two methods of compensation, and therefore, between the two instruments which are linked to them. However, the type of risks which underlies the use of mechanism can give a key to repartition of these two methods of compensation. Keywords : Risk, chance, uncertainty, causal relationship, all or nothing approach, discretionary power, prejudice, presumption, probability, proportional compensation, administrative liability, medical liability, victim.