30As has been consistently held, it is not enough in order to annul a decision on promotion that, during the comparative assessment of the merits of the candidates, the personal file of one of them was irregular or incomplete by reason in particular of the absence of a periodical report, except where it is shown that that fact could have had a decisive influence on the promotion procedure (see, for example, the judgment of the Court of First Instance in Case T-68/91Barbi v Commission [1992] ECR II-2127, paragraph 26). Thus, the absence of a periodical report is not determinative where the appointing authority has at its disposal the very widest powers to obtain all the information necessary to undertake a comparative examination of the merits of those eligible (judgment of the Court of Justice in Case 86/77Ditterich v Commission [1978] ECR 1855, paragraphs 18, 19 and 20).