At present, in China's judicial practice, the system of expert witness appearing in court and the system of expert debate have not been generally established, which affects the fairness of criminal trial to some extent. As Qian Lieyang, a famous lawyer, pointed out, the psychiatric appraisal book belongs to "verbal evidence" from the legal point of view, and belongs to the certificate issued by the appraiser of criminal cases. China's criminal procedure law requires that the appraisal conclusion should be signed and sealed by the unit, and the appraiser should also testify in court. However, in China's previous judicial practice, appraisers often do not sign, and even if they do, they rarely appear in court for cross-examination. Therefore, there are few cases where the expert conclusion is overturned in cross-examination. In this way, the responsibility of the appraisal conclusion falls on the unit, not the appraiser himself. When the judicial organ reads the appraisal book, it will only take effect if it reads the appraisal seal. One of the direct consequences of this is that it is difficult to cross-examine in court, and some irresponsible or "gray transactions" in the process of appraisal are legalized or covered up by the official seal of the "unit". Second, once a false certificate appears, it is impossible to investigate the appraiser's responsibility for perjury, because the appraisal certificate is a unit certificate. This causes the appraiser to have unlimited rights as a "second judge" or a "behind-the-scenes judge", but at the same time he is not responsible for his own actions. In fact, the official seal of the unit only proves the identity of the appraiser and cannot prove the correctness of the appraisal result. However, in practice, due to the formal effect, it replaces the scientific and correct identification content.

In order to change the above abnormal situation, we should strengthen and improve the judicial expertise system, learn from the practices of western countries, establish an expert witness cross-examination system in court, and change the current practice that appraisers only submit a paper of appraisal certificate to the court. That is, for some controversial appraisal results, the original defendant and the experts hired by the defendant explain their own appraisal basis in court, accept the other party's doubts, and finally the judge decides which appraisal opinion to adopt.

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