329. The precise and careful implementation of the procedures necessary for hearing and resolving challenges is a key requirement if the EDR system is to deliver electoral justice and credible electoral results. It is essential for the EDRB to ensure that all the legal personnel and support staff involved in the EDR system, whether permanent or temporary, have the training required and abilities needed for their technical work in keeping with the highest professional standards, including training to develop political sensitivity to electoral issues. Professional training encourages a public perception that the EDR system is ‘in good hands’. 330. Efforts have been made in several countries to promote professionalism, which is fundamental to the optimal organization of the electoral processes and the proper hearing and resolution of electoral challenges. Mexico has established the Centre for Electoral Judicial Training (Centro de Capacitacion Judicial) in the Electoral Court of the Judicial Branch of the Federation. Mexico’s electoral judicial career service is an example of good practice. It attracts professional staff and encourages constant professional improvement and sound performance on the part of the EDRB’s legal support staff. A staff training school has also been established, with the support of International IDEA, at the EDRB in the Dominican Republic. 331. In some countries EDRB staff members must take an oath before assuming their position to underscore their commitment and dedication to carrying out their role (see box 6.6). e) The cost and sustainability of EDRBs 332. The principle that democratic elections must be sustainable implies that EDRBs should be capable of carrying out their electoral responsibilities within any legally established deadlines, with ever greater effectiveness and efficiency and, if possible, at an ever reducing cost. 333. It is possible to identify a number of elements relevant to the medium- to long-term sustainability of an EDRB: (a) institutional sustainability, through an appropriate constitutional and statutory framework; (b) financial and economic sustainability, through an arrangement that ensures adequate financing; and (c) sustainability of human resources, by means of a sufficient structure of qualified support staff, with the aim of having the capacity to impart electoral justice effectively and efficiently. 334. To this end, the EDRB should establish procedures and practices that are realistic and cost-effective and that satisfy the needs of all the groups interested in electoral justice, both in the present and in the future. Accordingly, an assessment should be made of the real capacities of the EDRB and the human, financial and technological resources it has at its disposal. 114