¿Qué determina el éxito en unas Oposiciones?

In this article we analyze the selection process followed by 40.000 candidates to seven of the main Corps of functionaries in Spain. The evidence casts doubts on the design of the evaluation system. First, we find a high degree of randomness. A candidate's success depends on a number of factors unrelated to his quality, such as the weekday when he is examined, the moment of the day, a potential deferral and, specially, the order of evaluation. This randomness harms the selection process favouring those candidates that can afford to prepare and take the exam during a larger number of years. Second, we observe a series of evidences consistent with the existence of endogamy, sexism and localism in the evaluation. Candidates with relatives in the Corps to which they apply have larger chances of success. Moreover, their grades depend significantly on the characteristics of the committee and, revealingly, are similar to the rest of the candidates whenever an anonymous test has been performed. On the other hand, the characteristics of the evaluators also affect candidates' success according to their gender and origin. The author proposes the introduction of three simple reforms of the system: the performance of an initial test, the systematic use of anonymity and double external examination in all written exams and the implementation of quality controls by some independent supervision committee.