“The Impeachment Of The Expert Witness” In Criminal Procedure

Modern forensic science has been established more than one hundred years, the development of the science and technology can help the court find the fact of the case.However,by analyzing the causes of wrongful convictions that have been disclosed,researchers found that the expert opinion was one reason that cannot be ignored.The expert opinion is very complicated,the judges and the jurors as science layman cannot make a scientific evaluation for expert opinion.Besides,scientific evidence has inherent limitations,while for most of the general public, science means authority,as a result,they don’t have comprehensive awareness of the limitation of expert opinion.We should know that the science is just a highly probability assumption, despite the repeated verification,it still has the possibility of errors.For the expert opinion in the trial, we must uphold skepticism, through design a reasonable system to impeach its unreliability.In civil law countries’ criminal trial,there is only one neutral expert witness.The rest of the litigation participants are all science layman.They cannot make a strong impeachment for expert witness.As a result,false expert opinion is often adopted by the court.The common law system countries’ trial,there are two experts which are hired by two parties.The experts need to issue the expert opinion to the court and give his own lawyer assist in expertise.With the help of the expert,the lawyer can make impeachment on the expert’s qualification,the method,or the basis of the expert opinion to shake the credibility of the expert opinion.Compared with the civil law,the system of the common law is more useful to eliminate the wrong,unreliable expert opinion.The Criminal Procedure Law was amended in 2012,the expert need to appear in the court to provide the testimony,besides,expert assistant system is established.The purpose of the establishment of these two clauses is to establish impeachment proceedings against expert opinion.The common law is the reference in this paper,the author have made asystematic analysis on the impeach methods that the lawyer often use in the trial.In the last part,the author analysis the necessity and the feasibility of conduct impeachment in our country.In addition, the author have put forward the idea to improve the related systems,thus the impeachment can help the judge form the correct evaluation of the expert opinion in the trial.