专家辅助人的比较考察与制度重塑

Abstract： This article is not written to conduct comprehensive theoretical analysis of the expert assistant， but focuses on expert assistants' nature， coordination of conflicts of interest， boundary of responsibilities and other controversial issues in scientific and technological cases. These issues contain the core elements that affect objective and fair objects and determine the core rights and obligations of expert assistants. However， the above issues are regulated unclearly although they often appear in the trial practice， and arouse controversy among some scholars. Only if these issues are solved well， expert assistants would play the function better by using their science， technology or other expertise to help judges understand the evidence or determine the disputed facts.

Key words： expert assistant; science and technology; evidence

CLC： D 915                     DC：A                        Article ID：2096-9783（2021）01-0127-13

With the progress of science and technology and industrial upgrading， cases involving science and technology have been increasing. At the same time， expert consultants， expert assistants and technical investigators are widely used in the fields of intellectual property， environmental protection， medical services， financial innovation and other disputes. As a result， the expert evidence system has been taken more and more seriously. Some scholars keep relevant laws under review and make proposals for reform， in particular by recommending the enactment of legislation to clarify and modernize relevant laws. Some of proposals have led to reforming legislation. For example， the Rules of Evidence of Intellectual Property Rights issued by the Supreme People's Court in 2020， partly reflects some reform proposals. Regrettably， the new impact and challenges caused by the development of science and technology on the expert evidence system are not well dealt with， the theoretical basis of the existing system is still not sound， and legal norms of expert evidence are not systematic. To a large extent， such a system is incompatible with the judicial practice， which has affected the harmony of form and function. Considering that China belongs to the civil law system， this article carries out a comparative study with several typical common law countries. The article tries to set the targets to range from critical theory， to broad comparisons of entire systems， to narrower studies targeted to specific problems. However， the article does not mean to conduct comprehensive theoretical analysis of expert assistants， but focuses on expert assistants' nature， the coordination of conflicts of interest， the boundary of responsibilities and other controversial issues in practice.

1 How to Define "Person with Specialized Knowledge"

1.1  Why "Person with Specialized Knowledge" is Established

As far as complex specialized issues are concerned， it is helpful to first find the objective truth through strengthening the confrontation between expert witnesses. Second， the difficulty， high cost and long cycle of judicial authentication1have always been knotty problems for our judiciary. The introduction of persons with specialized knowledge may make up for or improve the shortcomings of the authentication system to a certain extent. They are helpful to find out the defects or errors of the authentication opinions by conducting cross-examination. At the same time， they can also express their opinions independently on specialized issues at comparatively low cost or more conveniently. Therefore， Article 61 of Several Provisions on Evidence in Civil Procedure Issued by the Supreme People's Court in 2002 stipulates that the parties may apply to the people's court for one or two persons with specialized knowledge to appear in court to explain the specialized issues. The judges and the parties may interrogate the persons with specialized knowledge who appear in court. With the permission of the people's court， persons with specialized knowledge who have been applied by the parties may cross examine the issues in the case each other. Persons with specialized knowledge may cross examine the authentication opinions. The above provisions were amended in 2019. Among them， Article 83 stipulates that in accordance with Article 79 of the Civil Procedure Law and Article 122 of the Interpretation of the Supreme People's Court on the Application of the Civil Procedure Law of the People's Republic of China， if a party applies for a person with specialized knowledge to appear in court， the basic information of the person with specialized knowledge and the purpose of the application shall be stated. The people's court shall notify other parties if it allows a party's application. Article 84 provides that judges may interrogate persons with specialized knowledge. With the permission of the court， the parties may inquire the persons with specialized knowledge， and such persons may cross examine each other as to the relevant issues in the case. Persons with specialized knowledge shall not participate in trial activities other than cross-examination of authentication opinions or expression of opinions on specialized issues.

Here， the subject matter and content of the above provisions after the amendment are basically unchanged， and four functions of persons with specialized knowledge are further clarified： cross examine authentication opinions; give opinions on specialized issues; answer inquiries from judges or parties; cross examine the relevant specialized issues each other. Since the latter two are the extended functions of expression of opinion or cross examination of authentication opinions， they are consistent with Article 79 of the Civil Procedure Law regarding the function that parties can apply to the people's court to notify persons with expertise to appear in court to deal with the authentication opinions or specialized issues.

1.2 Why an Expert Assistant is an Expert Witness

The above-mentioned "persons with specialized knowledge" are usually defined by academic and practical circles as "expert assistants". For example， the book "Understanding and Application of Judicial Interpretation of Evidence in Civil Litigation" compiled by the relevant judges of the Supreme Court writes： "Expert assistants refer to persons with special expertise or experience in science， technology and other professional knowledge. Those who are hired by the parties， with the approval of the court， appear in court to assist the parties in explaining or expressing opinions and comments on the specialized issues involved in the disputed facts." In this regard， some objections are raised. A scholar points out that the function and role of expert witnesses in litigation are confused with expert assistants in the current theoretical and practical circles， which is harmful to the development of legal theory and practice. In the trial， the parties may apply persons with expertise appear in court to explain professional issues， answer inquiries， and put forward their own opinions， which is convenient for helping judges and parties to accurately understand and determine professional issues. Such persons with specialized knowledge play the same or similar role as expert witnesses in the common law system， and the opinions provided by the persons may serve as the basis for the court to make judgments. Academically， such persons with specialized knowledge should be called "expert witnesses" or "testifying experts" who are different from the aforementioned "expert assistants"， who are created for cross-examination of authentication opinions. Such "experts" should belong to another type of "persons with specialized knowledge" stipulated by the current law. However， in a strict sense， the "expert witness" we have called here is an "alternative" that is fundamentally different from the expert witness in the common law system. Considering the beneficial experience and the elimination of inherent disadvantages of the witness system， the expert assistant may be called a paradigm that conforms to China's basic national conditions and cultural traditions. In short， our expert testimony system should include： authenticators， expert assistants and expert witnesses. They have different procedural functions in different situations[1].

All the same， there is a valid argument to be made in favour of expert assistants. This study states that the attack on the expert witness is carried out by the lawyer or the opposite party， and experts generally do not cross examine each other on professional issues in common law system. Therefore， it is reasonable to call a person with specialized knowledge an expert assistant in  his function to cross examine authentication opinions and to help the court determine the facts in issue. However， it doesn't mean that the expert assistant's cross-examination can be simply classified as auxiliary or secondary function. In fact， it is also an important expert opinion expressed by a person with specialized knowledge， which should also be classified as expert evidence in essence.

Specifically， first， the person who assists the court must be an expert. As mentioned above， an expert assistant is a person with specialized knowledge， that is， an expert with special expertise or experience in science， technology and other specialized knowledge. The court must determine whether the witness called is properly qualified to give the testimony. In the U.S. witness qualified as an expert by knowledge， skill， experience， training， or education， may testify thereto in the form of an opinion or otherwise2. The fields of knowledge which may be drawn upon are not limited merely to the "scientific" and "technical" but extend to all "specialized" knowledge. Thus， subjects that require expert testimony only involve "scientific， technical， or other specialized knowledge." Within the scope of the rule are not only experts in the strictest sense of the word， e.g.， physicians， physicists， and architects， but also the large group sometimes called "skilled" witnesses， such as bankers or landowners testifying to land values3. In civil cases， the subjects of expert testimony include intellectual property， technical contracts， accident reconstruction， engineering， handwriting analysis， insider trading， insurance， products liability， professional malpractice， property valuation， medicine， etc. In criminal cases， such as DNA， drug trafficking， trajectory trace inspection， etc. can be addressed by expert testimony.

Second， expert assistant's opinion must conform to specialized knowledge criteria. In China， the basis of expert opinion should be examined in court. The judges shall examine authentication opinions so as to confirm whether the following contents are included： the materials for the entrusted authentication; the basis of entrustment and the scientific or technological means adopted; specifications of the authentication process; a definite conclusion of authentication; specifications of the qualifications of the authenticators4. If any party concerned refuses to accept the authentication opinions made by the authentication institution designated by the court and applies for re-authentication， the court shall approve the application if the authentication institution or authenticator does not have relevant qualifications，     or there are obviously inadequate evidences for the authentication conclusions5. The above rules， like technical operation specification， are actually applied to expert assistants although they are not for expert assistants directly. Comparatively， in the U.S. the specialized grounds of the expert witness are examined in a much more detailed way. Expert testimony can be truly helpful， however， only if it is sufficiently reliable. Establishing that expert testimony is sufficiently reliable requires analysis of： （a） whether the theories， knowledge and data on which it is based are sufficiently reliable; （b） the witness who seeks to apply that knowledge in the case at hand is sufficiently educated， skilled and experienced in their application; （c） the witness has a sufficient factual basis to apply them; （d） the methodology employed is sufficiently reliable; and， where the expert seeks to express a specific conclusion as to key factual issues; （e） a sufficient nexus exists between considerations （a）-（d） on the one hand and witness' conclusions on the other.[2] In the U.K.， an expert witness should state the facts or assumptions on which his opinion is based. He should not omit material facts which detract from his concluded opinion. He should make it clear when a particular question or issue falls outside his expertise. If an expert's opinion is not properly researched because he considers that insufficient data is available then this must be stated with an indication that the opinion is no more than a provisional one6.

Third， an expert assistant's opinion belongs to admissible opinion evidence. As a general rule， opinion evidence is inadmissible. A witness may only speak of facts which he personally perceived， not of inferences drawn from those facts. However， there is one exception to this general rule： a qualified expert may express his opinion on a matter calling for the expertise which he possesses. His opinion may derive from information the expert has either personally observed or has otherwise been made aware of. Essentially， this means that as long as the expert's opinion satisfy the elements of Rule 702， it can be based on virtually any information available to the expert in a certain way. To determine whether expert testimony is required to establish an element or elements of a cause of action， courts consider whether the subject at issue is one "within the realm of the ordinary experience of mankind" and whether understanding the subject requires "special learning， study or experience."

To sum up， expert opinion is often necessary to explain to the judge or jury the scientific or technical background of issues that are central in a case， although the role of the expert opinion is not decisive of the issues. By its function and the very nature， the opinions expressed by expert assistants should be properly interpreted as expert evidence and should be included in the scope of expert evidence. An intelligent evaluation of facts is often difficult or impossible without the application of some scientific， technical， or other specialized knowledge. The most common source of this knowledge is the expert witness7. If an expert assistant is not identified as an expert witness， and is free from the rules of expert evidence， it is difficult to avoid the phenomenon of different judgments in the same or similar cases. Therefore， it is meaningless to distinguish an expert assistant from expert witness only by the way he states his opinion.

2 The Neutrality of Expert Assistants

Whatever we call an expert assistant， he is still an expert and shall observe the ethnical norms in lawsuits， because he owes a duty to the court which he must discharge notwithstanding the interest of the party calling him. However， different people have different opinions.

2.1 Ethnical Norms of Expert Assistants

Today， we still find it hard to collect comprehensive ethnical norms or codes of expert assistant in China， even there are still different understanding on who an expert assistant shall be responsible for. Some judges think that an expert assistant is employed by the party， so the way and content of his participation in the litigation determines that they will be consistent with the position of the client. Although we expect an expert assistant to be neutral， it is not realistic to ensure his neutrality through the system. Some people may doubt that if the requirements for neutrality of expert assistants are relaxed， the experts may be irresponsible and give their opinions wantonly， causing the trial out of control and affecting the judge's determination of facts.

This view also exists abroad. Some scholars think that anyone with any experience with the law in practice recognizes that it is utopian to deny partisanship between law and the ethical position of most disciplines. The expert must acknowledge being engaged by partisan counsel to a certain degree. Not only do most lawyers view this formulation as unrealistic， so too do most experts who choose to testify and who are aware that the matter to be addressed is in dispute. If there were no such dispute， there would be no need to engage them. Moreover， the expert is ordinarily aware that there will be expert evidence in opposition， that he/she will be sitting in the witness chair and not at an academic podium， and that there will be adversarial cross-examination and not deferential student questions[3]. In fact， it is not the case. If the expert assistant's professional opinion loses its partisanship， it will lose its value of existence[4].

Based on some phenomena， these views reveal the difficulties of experts' neutrality in reality. However， they are against the original intent and value of expert witness. It shall be realized that none of difficulties can be obstacles for experts to maintain an objective and neutral position. Even if the expert witness speaks on behalf of one party in the court， it must be based on scientific rationality. Especially， the charging of fees shall be prohibited if they are only based on the success or failure of litigation.

In western countries， scientific and professional organizations have insisted on ethics rules for over 100 years. At present， many countries put forward requirements on the neutrality of expert witness， and make it clear in the form of obligation or responsibility. Some codes of expert witness are also issued. In U.S. fidelity to the discipline and resistance to partisan pressures are emphasized in scientific code of ethics and the ideal of the expert as a disinterested educator is carried forward. For example， engineers shall issue public statements only in an objective and truthful manner. Engineers shall be objective and truthful in professional reports， statements， or testimony. They shall include all relevant and pertinent information in such reports， statements or testimony， which should bear the date indicating when it was current[5]. In England， Part 35 of the Civil Procedure Rules1998 （CPR） has been interpreted as imposing an obligation on an expert in civil cases to attend court if called upon and to take all reasonable steps to be available[6]. Lord Woolf stated that the overall objective of the CPR in the context of experts should be to foster an approach which emphasizes the expert's paramount duty to the court， not to the party who retains him[7]. Furthermore，many of the professional bodies that train and educate expert witnesses have also created their own Codes of Guidance for experts. Much of the provisions in the Codes set out by these professional bodies places great emphasis on the overriding duty owed by the expert to the court and the necessity for honesty， integrity， objectivity and impartiality at all times[8]. In Australia，part one of the Practice Direction commences by stating that experts have a general duty to the court which is paramount to the duty owed to the person retaining the expert. In 1.2 it is stated that an expert does not become a party's advocate "even when giving testimony that is necessarily rather than inferential." Many professional bodies in Australia whose members may be called upon to act as expert witnesses have also set out Codes to give guidelines to experts. For example， the Australian Council of Professions， a national organization which aims to promote professionalism and ethical practices within its member professions， adopted a guidance paper on the role and duties of an expert witness in litigation to which its members are required to conform when giving expert evidence[9].

Combined with China's conditions and the mature practices of foreign countries， the codes of expert witness with Chinese characteristics， in which expert assistant's ethnical norms are especially clarified， should be issued so that expert assistants can participate in litigation activities in accordance with the rules. For example， an expert assistant's opinion presented to the court should be independent or uninfluenced; an expert assistant should provide independent assistance to the court by way of objective unbiased opinion in relation to specialized issues; an expert assistant should never assume the role of lawyer. Especially， Article 1228 of the Interpretation of the Supreme People's Court on the Application of the Civil Procedure Law of the People's Republic of China should be amended timely， and opinions proposed by persons with expertise in court on the specialized issues must not be deemed as statements of the parties. The expert opinions are independent. For expert assistants， a position that permits them to "testify for the parties who hired them" and to act as a "servant of the court" may be adopted.

2.2 Conflict of Interest

In China， there are no systematic provisions of expert assistants. Even some judges don't know exactly what they can rely on to regulate the duties of expert assistants to the court. So it is not strange if different judges make different decisions towards the same issues. Let's look at two cases which dealt with disqualification for conflict of interest differently. In the case of infringement of invention patent between Nokia and Shanghai Huaqin Communication Technology Co.， Ltd.9， the appellant Nokia questioned the qualification of Zhang Wenguo， an employee of Huaqin company， as an expert assistant of the appellee. In this regard， the court held that： the Civil Procedure Law stipulates that a party may apply to the people's court to notify a person with specialized knowledge to appear in court and put forward opinions on professional issues. According to the above provisions， as long as the expert assistant has the expertise involved in the case， he can be entrusted to appear in court to give opinions on professional issues. The law does not prohibit the parties' employees as expert assistants to appear in court to give opinions on professional issues. In fact， the technical personnel of the company concerned may be the person who knows best the professional and technical issues involved in the case， and they can certainly appear in court to explain the professional issues. Moreover， the expert's opinions on professional issues can not be used as the direct basis for the judgment. Therefore， Zhang Wenguo， an employee of Huaqin Company， could appear in court as an expert assistant to explain issues， and Nokia's objection to his qualification could not be established[10]. However， In the case of contract dispute between Zhejiang Yijian Construction Group Co.， Ltd. and Jiashan Intercity Concrete Co.， Ltd.10， the court held that： the expert assistant had an interest in Yijian company， and his statement is inconsistent with the facts of the case， so his "testimony" was not confirmed[11]. According to the civil procedure law， if the authenticator has an interest with one party， he should disqualify himself， but there is no such provision for an expert assistant， which leads to differences between the two courts on whether such expert assistants facing conflict of interest may appear in court to express their expert opinions.

Let's look at the relevant regulations abroad. In England， a conflict of interest does not automatically disqualify an expert. It depends on whether his evidence is independent and the conflict is material or significant. And it is a question for the court and not the parties. If the conflict is material or significant， the expert's opinion should be excluded or ignored. Therefore， a party who wishes to call an expert with a potential conflict of interests of any kind should disclose the details to the other party and to the court at the earliest possible opportunity11. In Liverpool Roman Catholic Archdiocesan Trustees Inc v Goldberg （No 3）12， the expert was a good friend of the defendant on whose behalf he was called. The expert said that his personal sympathies were engaged to a greater degree than would probably be normal with an expert witness. It was held that this admission rendered the evidence unacceptable on grounds of policy： that justice must be seen to be done as well as done. However， it has also been held that an employee of a party can be an independent expert， provided that the party can demonstrate that the employee has not only the relevant experience but also an awareness of his overriding duty， as an expert witness， to the court13.

Clearly， it is not necessary for the expert witness to disqualify himself for the conflict of interest if he discloses the relevant details. The procedural laws in China stipulate that the parties may apply for the withdrawal of the authenticator orally or in writing， but it does mean that such provisions shall apply mutatis mutandis to the expert assistant. The court is entitled to make a comprehensive judgment to the disqualification according to the situation of the case， the degree of the conflict of interest and the justice consciousness of the expert witness， etc.

3 The Ultimate Issue Rule

According to Chinese law， the scope of activities of expert assistants should be limited and expert assistants can't participate in the trial activities other than professional issues. The limitation seems to be equivalent to the ultimate issue rule in the common law system in a sense. Because of the complexity of the issue， judges have always had difficulties in defining what elements constitute specific issues or ultimate issues.

3.1 Ultimate Issue Rule in Common Law System

At common law it has traditionally been unacceptable for an expert to give an opinion on any ultimate issue. The view has been that issues of fact are ultimately for the tribunal of fact to decide according to the standard of proof determined by law[12]. The justification of the rule is that such opinion might unduly influence the trial of fact. It prevents witnesses from usurping the function of the court： witnesses are called to testify， not to decide the case. Another concern is to prevent the finder of fact from being unduly influenced by an expert opinion， which may not be reliable， on an issue which the court has to determine. However， this rule has been criticized. As a result， it has been increasingly circumvented. The expert's opinion on the ultimate issue does not amount to the expert's final say. The charge of "usurping the function of the jury" against the expert has been rebutted with the observation that the jury could always reject the expert's testimony[13]. Rule 702 is the basic rule concerning expert witnesses. In essence， an expert witness may be employed if the expert has specialized knowledge that would be helpful in deciding the case correctly， and if the expert's testimony is sufficiently reliable to assist the fact finder. The intent of the Rule is to liberalize the admissibility standards for expert testimony14. However， although the rule has now been very much eroded， resurrection of the ultimate issue rule is reflected in insanity defense cases in Rule 704. The Advisory Committee Note to Rule 704 states， many modern decisions illustrate the trend to abandon the rule completely. The abolition of the ultimate issue rule does not lower the bars so as to admit all opinions. Under Rules 701 and 702， opinions must be helpful to the trier of fact， and Rule 403 provides for exclusion of evidence which wastes time. These provisions afford ample assurances against the admission of opinions which would merely tell the jury what result to reach， somewhat in the manner of the oath-helpers of an earlier day. They also stand ready to exclude opinions phrased in terms of inadequately explored legal criteria15. In England， Section 3 of the Civil Evidence Act 1972 provides that subject to any rules of court made in pursuance of Part I of the Civil Evidence Act 1968 or this Act， where a person is called as a witness in any civil proceedings， his opinion on any relevant matter on which he is qualified to give expert evidence shall be admissible in evidence. The above "relevant matter" includes an issue in the proceedings， so the giving of expert opinion on an ultimate issue is permitted. In Ireland， a flexible approach can be seen in some cases where the courts have recognized that a strict application of the exclusionary rule is not always appropriate. For example， Barron J. in McMullen v Farrell stated a belief that there are certain cases where professional witnesses are entitled to express their opinion on the question which the court has to decide. Despite the decline in the ultimate issue rule in Irish case law， the courts are very careful to avoid experts making widespread findings of fact， and it has been stressed in several cases that the judge cannot abdicate his role to the expert， no matter how distinguished16.

Generally， the basic approach to expert opinions in these rules is to admit them when helpful to the trier of fact. In order to render this approach fully effective and to allay any doubt on the subject， most countries in the common law system have moved away from a strict application of the ultimate issue rule. Thus， expert opinions as to ultimate issues are not objectionable and will be admitted if they will assist the judge to understand the evidence or to determine a fact in issue.

3.2 Ultimate Issue Rule in China

It is hard to say there is ultimate issue rule in China， although its essence lies on how to define professional issues. Because the legal boundary is not clear， the expert's usurpation exists in reality. It's not uncommon for experts to express their opinions beyond the professional issues or even on the results of a case. Judges usually only ask about their professional qualifications， and generally do not comment on the content of their speeches in court. When an expert presents convincing and impressive argument， peppered with technical terminology， the judge will not explicitly limit the scope of their opinions. One of the reasons is that they have little specific professional knowledge. In practice， where the judge is being asked to determine on inexperienced issues， and on which he is undecided， considerable deference will be given to the expert witness in a field. Secondly， Chinese judges are generally faced with more and more pressure and tend to hand over the thorny technical issues. That seems to be one of the reasons of over-authentication， repeated authentication and multiple authentications. In some cases expert witnesses aren't needed， however expert witnesses are applied to appear in court to express their opinions， which leads to the increase of time cost and money cost.

Nowadays， the Supreme Court has noticed these problems. For example， in the judicial interpretation of environmental tort litigation， the necessity of environmental tort authentication has been weakened， and judges are required to give full play to their trial responsibilities. Article 23 of the Interpretation of the Supreme People's Court on Several Issues concerning the Application of Law in the Trial of Environmental Civil Public Interest Litigation Cases provides that， if the cost of ecological environment restoration is difficult to determine or the authentication cost required to determine the specific amount is obviously too high， the people's court may have a final say in combination with the scope and degree of environmental pollution and ecological destruction， the scarcity of ecological environment， the difficulty of ecological environment restoration， the degree of ecological environment restoration， the degree of ecological environment restoration， the degree of ecological environment restoration， the degree of ecological environment restoration and the degree of ecological environment restoration， the operation cost of the pollution prevention and control equipment， the benefits obtained by the defendant due to the infringement， the degree of fault and other factors， and by referring to the opinions of the departments responsible for the supervision and management of environmental protection and the opinions of experts.

At the same time， in the Evidence Rules of Intellectual Property， the items of authentication are limited. It states that， however skilled or eminent， an expert can't usurp the functions of the judge. The function of any expert witness adduced is to help the court and not to usurp its power. He can give no more than evidence. In the past few years， there have been different approaches to whether or not to entrust authentication institution or authenticators to determine "equivalents" issues in patent infringement. Some courts entrusted some institutions to authenticate whether the accused device or process and the patent claim are "the same or equivalent". The conclusion of authentication is often directly used as the basis of courts' judgment. If so， it is easy to think that the court has given the duty of claim interpretation to the authentication institution， because the court's judgment is replaced by the expert opinion. For example， in the patent infringement case of "air conditioner of window type"17， the court of first instance entrusts the authentication institution to carry out the authentication. Among the entrustment items for authentication， there is one item "whether the accused infringing product and Liao Yafei's patented technical schemes are the same or equivalent". Based on this， the authentication institution came to the conclusion that the alleged products produced and sold by Kelong company and its Chongqing Office were not the same or equivalent as Liao Yafei's technical schemes. Accordingly， the court of first instance ruled that Kelon Company did not constitute infringement. One of the reasons for the appellant's appeal was that the court entrusted authentication matters improperly and handed over the infringement judgment to the authentication institution. In its judgment， the court of second instance held that： although the "principle of equivalents" and "doctrine of equivalents" are the principles and theories established by judges all over the world with the emergence of the modern patent system， they were dedicated to the determination of patent infringement， but "doctrine of equivalents" had the duality of technical terms and facts， and legal terms and facts. The determination of "equivalence" in the authentication opinion was from a technical point of view， and the conclusion of "equivalence" was a technical fact. To determine "equivalents" issues was not equal to judge the patent infringement， nor could it replace the trial function of the people's court. Whether infringement or not， the people's court should make a comprehensive judgment in combination with other evidence. Only the people's court's judgment of "equivalence" based on the evidence of the whole case was indeed "equivalence" in the judicial sense. Therefore， there was nothing improper about the matters entrusted by the court of first instance. Some scholar does not agree with it， and states that although the court hold that "equivalence" can be divided in technical and legal equivalence， this formulation has no sufficient basis. And the authentication opinion does often not to distinguish the technical equivalence from the legal equivalence， but make a direct conclusion of "equivalent or not"[14].

The newly amended Several Provisions on Evidence in Civil Procedure clearly stipulates that persons with special knowledge shall not participate in trial activities other than cross examination of expert opinions or expressing opinions on specialized issues. Article 19 of Several Provisions on Evidence in Civil Procedure provides that the people's court may entrust an authentication institution the following specialized issues concerning the facts to be proved： （1）The similarities and differences in the means， functions and effects of the corresponding technical features between the accused technical scheme， the patent technical scheme and the existing technology; （2）The similarities and differences between the accused works and the claimed works; （3）The similarities and differences between the trade secrets claimed by the parties and the information known to the public in their respective fields， and between the  accused information and the trade secrets; （4）The similarities and differences of the characteristics between the accused objects and the authorized varieties of plant ， and whether the differences are caused by non-genetic variation; （5）The similarities and differences between the accused layout design of integrated circuit and the claimed layout design of integrated circuit; （6）Whether the technology involved in the contract has defects; （7）The authenticity and integrity of electronic data;（8）Other specialized issues that are needed to be entrusted for authentication. Improper boundary of professional issues may affect handling of cases. Through the provision， we can see that the judicial interpretation limits specialized issues in the form of enumeration. Although the expert's opinion is not binding and is open to the court to place little weight on the evidence， such issues as determination of patent infringement， equivalents， or trade secret are clearly identified as the powers or duties of the court. The provision is also applied to expert assistants. It is a useful benchmark for the expert assistant to ensure that he does not overstep the red line and stray outside the specialized field.

Generally， we need adopt the ultimate issue rule but limit the scope of ultimate issues. This is common practice in the world. However， how to determine the scope of ultimate issues or specific issues， we still have a lot of work to do. It should be remembered that the first function of expert assistant is to provide the judges with the necessary specialized knowledge to come to their final conclusions. Even judges need information about the background to the ultimate issue where necessary or conveniently， and it must be ensured that expert assistants do not usurp the role of judges to determine facts in issue and the final say about ultimate issues.

4 Problems and Experience in Comparison

Expert evidence has been widely used in the common law system， and it can be seen in  western movies and news. An expert witness can be seen in almost every legal play， and the role of expert opinion is prominent in relevant legal news. Because of its long history， the Western expert witness system is relatively mature， and has played an important role in the litigation process and professional field. However， it is worth noting that there are some drawbacks in the above system， and at the same time， calls for reform are often heard.

4.1 Differences of Background

The expert witness is originally the product of the adversary system. The adversary system has three main characteristics： （1） the process of litigation and the process of proof are dominated by litigants; （2） the factual issues are tried by jury and the main duty of the judge is to gate-keep the evidence and to make a legal judgment on the case; and （3） there is a centralized trial. The designers of the adversarial system believe that if the two sides engage in a "legal battle，" they will try to find evidence which is beneficial to them and actively attack the evidence of the other side. In this way， the necessary information can be submitted to the impartial and neutral trier of facts to make a right judgment.

However， the principle does not apply in practice in China due to  the judge's extensive power to supervise and direct the process. During the trial， the judge plays an active role in questioning witnesses， framing or reformulating the issues. In addition， the court may obtain certain types of evidence， such as expert opinions， on its own motion. Such differences between the two legal systems tell us that we cannot copy easily the rules of expert witness at common law to deal with our expert assistant opinion.

Even so， some good experience of an adversary system can be drawn on. Expert witness system has been widely used in common law countries since its creation. The distinctive antagonism of an expert witness system is not only the embodiment of the judicial tradition of common law system， but also in line with the requirements of the principle of efficiency. We should further enhance the confrontation of the parties in the trial， and let the expert assistants give full play to the role. In order to win the favor of judges， expert witnesses try their best to make trouble for each other and question each other's opinions. Through the various means of attack and defense of both parties， the judge can more effectively and accurately find the truth of the case. From the engagement of the parties to the assistance of the parties， it not only ensures the dominant position of the parties， but also shows a high degree of transparency and openness， which ensures the procedural justice[15].

4.2 High Cost and Undue Delay

It seems that there are two main causes for high costs in some cases in common law system： one is uncontrolled evidence discovery， and the other is an uncontrolled expert witness. For example， in some complicated environmental cases， several experts may appear in court to testify through their expertise. Three issues may cause undue delay： （1） it takes time to prepare an expert report; （2） duration of evidence discovery is prolonged by the expert's lengthy report; （3） procedure is prolonged by cross-examination. At common law， anyone with specialized knowledge or skills can become expert witnesses. When selecting expert witnesses， the parties often consider whether the expert witnesses are good for them to win the lawsuit. A few expert witnesses maybe give testimony good for the party just for economic gain. Under this circumstance， the impartiality of expert evidence is hard to secure.

In China， as the action proceeds， the judge may obtain expert opinions on its own motion. Being available in court and conducting cross-examination for an authenticator are different. In order to avoid litigation delays caused by excessive use of expert testimony， the expert reports should be allowed to be submitted and questioned in written form in court. Only when one party objects to the opinions or the court deems it necessary for the authenticator to testify at court， it is necessary for the authenticator to appear in court for testimony. It should be helpful to tackle the time delay and high cost. However， we must stick to the principle that the expert opinion should not be admitted in court if she/he refuses to testify at court after the notification of the court.

Although the Civil Procedure Law provides that the authenticator shall appear in court for testimony on the condition that one party objects to the opinions or the court deems it necessary for the authenticator to testify at court， some authenticatorsstill refuse to appear in court to testify in lawsuit， so the cross-examination of expert assistants as to authentication opinions can't be safeguarded. From the authenticator's perspective， there are three reasons for the low rate of an authenticator appearing in court. First， there is no strict legal liability for authenticator's refusal to appear in court. The Civil Procedure Law only provides that where the authenticator refuses to testify at court even after the notification of the court， the authentication opinions shall not be taken as the basis for ascertaining the facts and the party paying authentication expenses may request a refunding. There is no punitive measure for such kinds of authenticator， and the deterrent efforts are obviously insufficient. Second， there is no economic compensation for an authenticator appearing in court to testify. In some circumstance， the transportation and accommodation expenses are even higher than authentication expenses. Moreover， no parties are willing to pay them. Third， some judges are inclined to use written opinion based on judicial efficiency.

To change this situation， we may improve the system in the following ways. First， the system shall provide that appearing in court to testify is a mandatory duty of an authenticator. If necessary， punitive measures for authenticator such as fines， revocation of licenses， and so on， should be added in the law. Second， the system shall provide economic compensation for authenticator to testify in court. The reasonable expenses to appear in court should be paid equally by both parties in advance， and afforded by the losing parties at last. Third， the judge cannot transfer the duty of examination of the specialized issues to an expert assistant. The judge's over-reliance on expert written opinion will impair the reliability of the authentication. The judge must remember that an authenticator's appearing in court to testify is a principle not an exemption. Otherwise， it will damage the value of cross-examination and enlarge the function of expert assistant eventually， which results in injustice.

4.3 Comprehensive Pools of Experts

Expert witnesses in the common law system are generally well developed and well regulated. In the event of disputes， experts can be easily found. This is closely related to the perfect pool of experts. With the vigorous rise of a new round of scientific and technological revolution and industrial change， new technologies， new products and new business forms continue to expand the legal boundaries， and new scientific and technological issues continue to emerge， such as the Internet， big data， artificial intelligence， standard essential patents， biomedicine and other cutting-edge issues. It is necessary to analyze complex technical solutions and flexibly apply the law in specific cases. In China， courts at all levels have further clarified the ways for all kinds of personnel to participate in the technical fact investigation to make full use of all kinds of resources of the technical investigation， and construct an organic and coordinated mechanism for finding out the technical facts. The Supreme People's Court has established a national database of judicial technology investigators and technical consulting experts， established a national court technology investigation resource sharing mechanism， and issued the "technical investigator's work manual （2019）" to provide work guidelines and paradigms for national courts to find out technical facts. Beijing Intellectual Property Court has established a system composed of professional people's jurors， technical investigators， expert assistants and expert consultants. In the process of evidence preservation， the Court of Xinjiang Production and Construction Corps employed professionals to participate in the infringement investigation. The High People's Courts of Hubei， Hunan， Sichuan， Shanxi and other places set up expert database to give full play to the professional support role of experts and improve the accuracy of judges in finding out technical facts[16].

Even so， it is still difficult to find qualified experts after the occurrence of some special disputes involving science and technology. So we suggest that the national database of expert witnesses be timely supplemented according to the needs of judicial practice and some regional databases of experts be established according to their geographical features. Moreover， the database should set up lists of different expert witnesses according to different fields. Furthermore， the specific requirements for expert witnesses should not be limited to working years， scientific research works or something else. Of course， the pool of experts aims to help litigants and courts find proper experts in litigation. This doesn't mean an expert who is not listed in the above pools cannot appear in court. Whether a person can be a qualified expert witness depends on the discretion of the court according to the litigation circumstances.

4.4 Guidance Cases

Continuity and predictability of the law are positive attributes. In any legal system， the opinions of judges in disputes are likely to be of interest in subsequent cases with similar facts. If a judge assumes that earlier decisions in his court and in higher courts were dealt with competently， there is no reason to suppose， in the absence of changed circumstances that a similar result would be inappropriate. Precedent is often noted in a civil law decision as teaching something， a use which refers to the form of assistance written decisions provide in determining how statutory law ought to be interpreted. Where precedent becomes a primary source of law， as in common law systems， the case does more than teach judges something， it exists separately as laws to be followed， or distinguished. In some countries， a series of precedents have not only solved the disputes in involving science and technology， but also established many important legal principles of expert witnesses[17]. Their experiences are worthy of study.

China has no precedent system， but the typical cases and the guiding cases have played an important role in making up the gaps of statutory law to a certain extent. At present， China is in an important period of innovation. In respect of the specialized disputes， the expert witness system should further be improved. In recent years， the Supreme People's Court and some provincial and municipal courts have issued some typical or guiding cases involving expert assistant system that are helpful to unify the applicable standards of law. To develop the doctrine of expert assistants and satisfy the practical need， the courts should enrich guidance cases continuously， especially issue timely the typical or forward-looking cases as to ethnical norms， ultimate issues or admissibility of expert witnesses， etc.

Reference：

[1] Bi Yuqian. Review of the Functional Positioning and Legislative Omissions of the Expert Assistant System[J]. Research on the Rule of Law， 2019（5）： 75.

[2] Clifford S. Fishman and Anne T. McKenna. Expert Witness Testimony in Civil Cases： An Overview，Jones on Evidence[M]，7th ed，§ 41： 2.

[3] Geoffrey C. Hazard， Jr.， Michael J. Saks and Joseph Sanders. Ethical Standards of and Concerning Expert Witnesses[M]. Modern Scientific Evidence，2017： 22.

[4] Bi Yuqian. Identification and Analysis： Civil Iitigation Expert Assistant[J]. Comparative Law Research， 2016（2）： 99-111.

[5] National Society of Professional Engineers. Code of Ethics for Engineers， Section II， 3a. 2013： 1-3.

[6] Civil Justice Council. Protocol for the Instruction of Experts to Give Evidence in Civil Claims[EB/OL]. [2021-1-19]. https：//www.civiljustcec.gov.uk/914.htm.

[7] Lord Woolf. Access to Justice. Final Report， HMSO 1996： Ch.12-13.

[8] Law Reform Commission. Expert Evidence[M]. 2008： 174.

[9] Law Reform Commission. Expert Evidence[M]. 2008： 181.

[10] Shen Minglei， Dong Leilei. Research on the Application of Expert Assistant System in Civil Litigation[J].Application of Law， 2017（1）： 79.

[11] Shen Minglei， Dong Leilei. Research on the Application of Expert Assistant System in Civil Litigation[J]. Application of Law， 2017（1）： 80.

[12] Raymond Emson. Evidence[M]， 2nd Edition： 366.

[13] J. Wigmore. Wigmore on Evidence[M]. 1989， § 1920.

[14] Yan Wenjun. Scope of Patent Protection[M]. Law Press， Second Edition： 650.

[15] Liu Zhongwei. Perfection of the Expert Assistant System[J]. Journal of Henan Administrative Institute of Politics and Law， 2015（2）： 171-181.

[16] The Supreme Court. Judicial Protection of Intellectual Property Rights in Chinese Courts. 2019.

[17] Mary A. Glendon Michael W. Gordon Paolo G.Carozza. Comparative Legal Traditions[M]. Law Press China， 2nd Edition： 262-263.

專家辅助人的比较考察与制度重塑

——以科技类证据在诉讼中的运用为视角

张红生

（安徽省高级人民法院 立案二庭，合肥 230031）

摘    要：本文重点不在于从学理上对专家辅助人做细致的分析研究，而旨在尝试解决涉及科学技术类纠纷案件中专家辅助人的几个难题。比如专家辅助人的定位、利益冲突的处理、专家意见的边界等。这些问题决定了专家辅助人的核心权利义务，包含着影响专家辅助人客观公正地发挥职能的核心要素。对这些问题，法律规定不清，学者争议较大，但审判中又必须面对。解决好了这些问题，则可以更好地发挥专家辅助人运用其科学、技术或者其他专门知识帮助法官理解证据或者确定争议事实等方面的功能。

关键词：专家辅助人;科学技术;诉讼证据