2002-03 Kevin Barnard, Nichola Gray and Earl Hodges: Expert Evidence: Difference between revisions

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<LI>Author unknown, <I><U>Causation in medical malpractice cases</I></U><FONT FACE="Trebuchet MS,Arial" COLOR="#000080"> </FONT>Available on-line <A HREF="http://plague.law.umkc.edu/cases/vaccines/Callahan_v_Cardinal_Glennon_Hosp.htm">http://plague.law.umkc.edu/cases/vaccines/Callahan_v_Cardinal_Glennon_Hosp.htm</A> 23 March 2002</LI>
<LI>Author unknown, <I><U>Causation in medical malpractice cases</I></U><FONT FACE="Trebuchet MS,Arial" COLOR="#000080"> </FONT></LI>
 
<LI>Baile<I>y </I>L<I> et al &quot;<U>Reference Guide on Epidemiology</I></U>&quot; </LI>
<LI>Baile<I>y </I>L<I> et al &quot;<U>Reference Guide on Epidemiology</I></U>&quot; </LI>
<LI><A HREF="http://www.benecke.com/">Benecke M</A> <I><U>A Brief History of Forensic Entomology</U> (2001</I>)<B><I> </B></I><U>Forensic Science International</U><B> </B>Vol. 120, p. 2-14 Available On-Line <A HREF="http://www.benecke.com/briefhist.html">http://www.benecke.com/briefhist.html</A> 22 March 2002</LI>
<LI>Benecke M <I><U>A Brief History of Forensic Entomology</U> (2001</I>)<B><I> </B></I><U>Forensic Science International</U><B> </B>Vol. 120, p. 2-14</LI>
 
<LI>Benecke M and Lessig R <I>Child neglect and forensic entomology</I></A> Forensic Science International 120 (2001) 155-159</LI>
<LI>Benecke M and Lessig R <A HREF="maden.html"><I>Child neglect and forensic entomology</I></A> Forensic Science International 120 (2001) 155-159</LI>
<LI>Burchell and Milton <I>Principles of Criminal Law</I> 2000 Juta: Cape Town</LI>
<LI>Burchell and Milton <I>Principles of Criminal Law</I> 2000 Juta: Cape Town</LI>
<LI>Erdreich, L  &quot;<I><U>Using Epidimiology to</U> <U>Explain Disease Causation to Judges and Juries</I></U>&quot; in Carson D &quot; <I><U>Professionals and the Court: A Handbook for Expert Witnesses</I>&quot; </LI>
<LI>Erdreich, L  &quot;<I><U>Using Epidimiology to</U> <U>Explain Disease Causation to Judges and Juries</I></U>&quot; in Carson D &quot; <I><U>Professionals and the Court: A Handbook for Expert Witnesses</I>&quot; </LI>
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</U><LI>Goldberg R <I><U>Causation and Risk in the Law of Torts: Scientific Evidence and Medicinal Product Liability</LI>
</U><LI>Goldberg R <I><U>Causation and Risk in the Law of Torts: Scientific Evidence and Medicinal Product Liability</LI>
</I></U><LI>Jones AJ <I>Medical Negligence</I> 1991 Sweet and Maxell: London</LI>
</I></U><LI>Jones AJ <I>Medical Negligence</I> 1991 Sweet and Maxell: London</LI>
<LI>Lamm, S &quot;The Epidemiological Assessment of the Safety and Efficacy of Bendectin&quot; Available On-Line <A HREF="http://www.hyperemesis.org/medication_misc.htm">http://www.hyperemesis.org/medication_misc.htm</A> 21 March 2002</LI>
<LI>Lamm, S &quot;The Epidemiological Assessment of the Safety and Efficacy of Bendectin&quot; 21 March 2002</LI>
<LI>Mendelson, G <I><U>Forensic Psychiatry: The  Civil Practice</LI>
<LI>Mendelson, G <I><U>Forensic Psychiatry: The  Civil Practice</LI>


</I></U><LI>Morten St&aelig;rkeby <I><U>Introduction to Forensic Entomology</I></U> available online <A HREF="http://folk.uio.no/mostarke/forens_ent/introduction.shtml">http://folk.uio.no/mostarke/forens_ent/introduction.shtml</A> 21 March 2002</LI>
</I></U><LI>Morten St&aelig;rkeby <I><U>Introduction to Forensic Entomology</I></U>21 March 2002</LI>
<LI>Snyman <I>Criminal Law</I> (1995)</LI>
<LI>Snyman <I>Criminal Law</I> (1995)</LI>
<LI>US Department of Justice <I>H<U>andbook of Forensic Services: Evidence ExaminationsóToxicology</I></U> Available on line <A HREF="http://www.fbi.gov/hq/lab/handbook/examtox.htm">http://www.fbi.gov/hq/lab/handbook/examtox.htm</A> at 23 March 2002</LI>
<LI>US Department of Justice <I>H<U>andbook of Forensic Services: Evidence ExaminationsóToxicology</I></U> at 23 March 2002</LI>


<LI>Van der Westhuizen, J  <I><U>Forensic Criminalistics </I></U>(1996) Heinemann: Johannesburg</LI>
<LI>Van der Westhuizen, J  <I><U>Forensic Criminalistics </I></U>(1996) Heinemann: Johannesburg</LI>
<LI>Wager B <I><U>The Testimony of Bugs ñ Forensic Entomology </I></U>Available On Line <A HREF="http://www.main.com/~brad/techrep/techrep.htm">http://www.main.com/~brad/techrep/techrep.htm#What</A> 22 March 2002</LI></UL>
<LI>Wager B <I><U>The Testimony of Bugs ñ Forensic Entomology </I></U> 22 March 2002</LI></UL>


<P>Internet presentation by <A HREF="http://www.benecke.com/">Mark Benecke</A></p>
<P>Internet presentation by Mark Benecke</p>
<hr>
<hr>
(c) 2002 by Kevin Barnard*, Nichola Gray and Earl Hodges
(c) 2002 by Kevin Barnard*, Nichola Gray and Earl Hodges

Revision as of 12:09, 14 December 2011

Expert Evidence


By Kevin Barnard*, Nichola Gray and Earl Hodges


*g99b2365@campus.ru.ac.za (Rhodes University, South Africa)


A. INTRODUCTION

The use of expert evidence is increasing in the determination of the outcome of trials. It becomes increasingly evident that you have to examine the methods used by the experts in arriving at their conclusions, to determine whether such evidence has a large probative value. What this essay endeavours to do is to examine how expert evidence can be used to prove causation.

WHAT IS AN EXPERT

An expert who makes his or her personal knowledge and experience available to a court to help it understand the issues involved in a case is known as an expert witness.

B. CAUSATION

According to Jones, causation concerns the "physical connection between the defendantís negligence and the plaintiffís damage". He submits that it does not matter how blatant the defendantís negligence was, he would not be liable should his conduct not be shown to have caused the damage. There must thus be a connection or causal link between the initial act or omission and the resulting consequence. Thus causation can be said to refer to the concept that not every accident results in injury and that not all injury is the result of someone else's negligence. We are essentially trying to find out how the damage occurred .

Jones states that in medical malpractice litigation causation is "largely a matter of medical and scientific evidence". He suggests that the question is normally dealt with by the "but for" test, but submits that even if this test is satisfied, another question must be asked, namely whether the defendantís conduct is the legal cause of the loss.

Now that a basic understanding of causation has been established, a more in depth analysis now follows. As mentioned above, there are two types of causation, factual causation (what actually caused the damage), and legal causation (what in law caused the damage).

FACTUAL CAUSATION

As can be seen from the International Shipping extract, in factual causation or the conditio sine qua non test, one has to ask the question whether, but for the accusedís conduct, the consequence in question would not have occurred at all or when it did. If the answer to this question is yes, then the conduct of the accused is the factual cause of the consequence. This is however not the end of the matter, the legal cause of the consequence must now be determined.

LEGAL CAUSATION

When determining legal causation, we have to examine whether the wrongful act is "linked sufficiently closely or directly to the loss for legal liability to ensue" or whether the loss is too remote.

Snyman says that "An act is a legal cause of a situation if, according to human experience, in the normal course of events, the act has the tendency to bring about that type of situationÖ"

Burchell and Milton state that in legal causation, what must also be looked at is whether there was an intervening event, which would break the "chain of causation". Such an event would be called a novus actus (or nova causa ) interveniens. The case of Loubser below illustrates this point.

The question was whether X was the cause of Yís death. The court considered whether the conduct of Y was unreasonable in the circumstances. If they had found that the conduct was unreasonable, it would have qualified as a novus actus interveniens. Rumpff J however found that it was "not abnormal for a person living in a rural environment to do what Y had done and accordingly X had caused Yís death".

That concludes the discussion on causation. The next part of this essay deals with the way in which expert evidence can be used to determine causation.

C. HOW EXPERT EVIDENCE IS USED TO ESTABLISH CAUSATION

This section is broken down into the various fields of expertise and a discussion of how each field can be used to establish causation.

FORENSIC ENTOMOLOGY

Forensic entomology can be said to be the application of the study of insects and other arthropods to legal issues. Stærkeby states that it can be divided in three sub fields: urban, stored-product and medicolegal. What concerns us is the medicolegal aspect.

Expert evidence in this field is mainly used to establish the time of death of the victim. This can help identify whether a suspect was at the crime scene when the victim died. Expert witnesses are called in to examine the insects and arthropods found on the bodies, and through an examination of their stage of development, can determine when death occurred.

Figure 1 [see .pdf file (click)]

The Chinese lawyer and death investigator Sung Tzíu reports the first documented forensic entomology case in the 13th century in the medico-legal textbook Hsi Yuan Lu. "He describes the case of a stabbing near a rice field. The day after the murder, the investigator told all workers to lay down their working tools (sickles) on the floor. Invisible traces of blood drew blowflies to a single sickle. So confronted, the toolís owner confessed."

Wager notes that if there is a high rate of infestation or egg laying around genital areas on the victim, then it is a sign that rape or sexual assault took place.  He states that blowflies would be attracted to the tiny lacerations and blood remains in these regions. Similar higher concentrations of eggs would be found around wounds.  Blowflies, he says, "look for recent wound openings."  Higher concentration of blowfly activity in regions can show that trauma occurred there.  For example, blowflies would most commonly lay their eggs around scratches received by the victim in an attempt to defend him or her self.

In other instances, Wager says forensic entomologists can be used to prove the cause of death. Examples are cases where child abuse and murder of infants have occurred through the use of insects like bees and wasps, either as forms of punishment or as a weapon of murder to that child".
 

In his article, Benecke gives the following example where forensic entomology was used to ascertain whether the cause of a childís death was poisoning by the drinking of sulphuric acid.

In another example from Benecke, one can see how forensic entomology can determine the cause of marks on the body.

Benecke and Lessig note that in earlier times, the main focus was on cockroaches, which "feed on dead or weakened persons". These types of cases are however seldom seen today.

A recent case example given by Benecke and Lessig illustrates how forensic entomology can today be used prove causation. The case used is a German one, where, during an enforced eviction, the body of young child was found. "The body showed signs of greenish discolouration and skin slippage." There were clear signs of neglect. The questions facing the court were, how long the child had been neglected, and when had the child died. In this case separate maggots were collected from the face and anal-genital areas. The entomological evidence established that "it was highly likely that neglect set in earlier, maybe even much earlier than the death." Benecke and Lessig point out that this would mean that the child could have been saved had legal action been carried out. This could set up a case against the social workers because it could establish a causal link between their omission and the harm suffered.

It can thus be seen from the examples given that expert evidence in the field of entomology can be used to establish causation. It can help prove that the alleged aggressor did not cause the marks or cuts on the body, although, as noted above, this is seldom the case now. Now it is seen that entomology can be used to prove neglect, as in the above-mentioned case as well in the case of sick or elderly people.


EPIDEMIOLOGY

Epidemiology is the study of the distribution of disease in populations and of the factors that affect this distribution. In contrast to clinical medicine where the emphasis is on the individual, epidemiology involves the examination of patterns of disease in groups of individuals

Its use in expert evidence has increased given the uncertainty faced by courts in proving injury causation and costs in respect of litigation concerning vaccines, and certain drugs and ñ especially in America- diseases related to radiation.

It is submitted by Erdreich that the expert witness is useful in that he can provide background information to counteract the beliefs and underlying assumptions of disease causes that may be held by a judge or a jury. Such assumptions often have the effect of faulty and illogical conclusions about causation being reached

Epidemiology, with particular reference to pharmaco-epidemiology, provides a probabilistic approach to causation. Evidence tendered is very numerical and statistical and draws attention to the probability of the consequence flowing from that which it is alleged to flow (the agent).

The epidemiologist deals mainly with the probability of two incidents occurring at once, or flowing from each other. Evidence given by the epidemiologist, if it shows that the probability of the causal link is very low, will impact heavily on the award of damages and more adversely on the success of the suit itself.

The epidemiological study involves a calculation of risk that an agent caused a disease (this is a relative risk). This, in laymanís terms, means that the agent has no effect on the incidence of disease. When the risk reaches a calculation of 2:1, this means that there is a 50 % chance that the agent has caused the disease. Anything greater than this allows the trier of fact to draw an inference that the agent was more likely than not the disease complained of by the plaintiff.

It is highlighted that epidemiology is a science which will impact upon other fields in which expert evidence can be used to prove causation. One such field is the field of the causal link, in delictual claims, between the ingestion of a drug and any illnesses or defects that ensue (A discussion of this will follow).

Expert evidence, if the witness explains simply, provides the court with an insight into the calculation of risk and the probability of the establishment of a causal link between agent and consequence.

The case of Reynard v NEC Corporation came into focus at the time when it was believed that the use of cellular phones was the cause of cancer-related deaths. The plaintiff in casu sought to sue the defendant for damages after she had been diagnosed with a brain tumour a few months after she had been in possession of a cellular phone.

The way in which the expert witness was used to prove (or disprove) causation was by drawing the courtís attention to the frequency of the use of cellular phones in terms of the probability of a person owning one such item; and then examining the probability of a brain tumour occurring in a population. It was given in evidence that, although brain tumours were relatively rare, in the American population, on average, 11 000 deaths occurred from this type of cancer per year. It was pointed out that without the help of additional data or information, it would be difficult to prove the question of whether the use of the phone was likely to cause the disease suffered by the plaintiff, or whether the two incidents had occurred together simply by chance.

Similarly, in the case of Bendure v Kustom Signals the cause of testicular cancer was in issue. Again, expert evidence was used to help the court in comparing the frequency of cancer found in police officers who used radar devices, as opposed to the frequency of cancer in those who did not.

Epidemiology, in these legal disputes raised at least three issues:

  1. Were the research methods used trustworthy and were they complete?
  2. If so, is exposure to the agent associated with the disease?
  3. If the agent is associated with disease, is it a causal relationship.

In both cases, the expert witness showed the need for a more thorough research to be conducted, and while the agent was associated with the disease, one could not go as far as stating that it was a causal relationship in the individual case. There was no proximate cause.

The use of the epidemiologist comes through in delictual cases when a causal link has to be established between an agent and a psychiatric disorder. The expert witness proves the causal link in much the same way as it is done for alleged harm suffered from radiation. By proving not only an association, but also a high probability of causation, since mood disorders cannot be attributed to any single cause.

Expert evidence as far as epidemiology is concerned goes a long way to proving that association is not causation. For example, in the cases above it is apparent that radar devices and the use of cell phones is associated with cancer. But it may not be the cause of cancer in individual cases.

In conclusion, epidemiology focuses on the incidence of disease in a population and does not tackle individual causation. This, one may argue, is a disabilitating limitation of the science. One may further argue that if specific causation is beyond the realm of epidemiology, the use of such expert testimony proves useless. The rebuttal of this submission, by Bailey et al is supported. The learned authors still value the testimony of the epidemiologist in that, especially in toxic substance cases, the plaintiff must not only establish that the agent is capable of causing disease, but also that it did in fact cause the disease.

CAUSATION IN THE FIELD OF MEDICINE

With the development of new drugs, the need to develop a scientific approach to causation, risk and probability of adverse reactions has been the accompaniment.

In this section of the essay, the writers focus on the way in which expert evidence can be used to prove causation

From the onset, it must be recognised that it is difficult to prove causation from medical products as one writer puts forward. The difficulty arises as medicines are administered to people already sick or those who are prone to further ailments. Also, the patient may be prone to allergic reactions, in general. Also, what may seem to one as an allergic reaction may turn out to be a case of a toxic reaction.

Earlier in the essay, factual causation was studied. This factual causation has bearing on the subject of causation in medical products.

In delictual claims, the plaintiff will not be successful unless it is shown that, had it not been for the defendantís conduct ñ or the consequence of the agent- the plaintiff would not have suffered loss.

The conditio sina qua non test is rejected in medical product liability. The reason for this that the test is too restrictive. A drug may be the only active cause of an adverse reaction. At the same time, the drug may have a negligible effect on the injuries.

There are situations, too, where the harm would have occurred in any event. One such example is the case of Barnett v Chelsea and Kensington Hospital

Expert evidence in the above case was used to prove that there was no causal link between the doctor not treating the patient and his death. Such evidence would infer a thorough knowledge of the effects of arsenic poisoning and the effects of exposure to the poison.

Where the drug has caused harm, yet it is not obvious that the drug itself was the only cause of harm, this would be an area where the testimony of the epidemiologist would indicate whether the other possible causes of the harm ought to be rejected.

The field of medicine is very wide. For this reason, , two case studies will be chosen in which to examine the way in which the expertís testimony can be used to prove (or disprove) causation in civil cases involving medicinal products and liability. Particular emphasis will be placed on case law.

BENDECTIN AND CAUSATION

Bendectin was a widely used drug for the treatment of nausea in the first trimester of pregnancies. This drug was discontinued in America in 1983 as it was alleged to be the cause of birth defects. However, research done by the Birth Defects Monitoring Program in the USA was not able to establish scientific causal link between the use of the drug and birth defects in children. This finding of no causal link between drug and defect has additionally been the outcome of American litigation, where the link has not met the standards of both legal and scientific criteria

In American Jurisprudence, the leading case on causation and medical products is the case of Daubert v Merrell Dow Pharmaceuticals.

The claim in the Daubert case failed because of the fact that the expert witnesses could prove neither factual nor legal causation. This case demonstrates the value of the expert witness who can use epidemiological studies of probability and risk to show that there was any evident risk in the use of Bendectin and any resultant birth defects that could flow.

What appears to have been the fault in the Daubert case is the fact that the witnesses called by the plaintiff focused on general causation, which the epidemiologist would refer to as simple association. Additionally, where the other party had the upper hand was in bringing to court an expert witness who could prove that this general causation was not specific in the case at hand.

The treatment of expert evidence and its use in proving causation in the United Kingdom is similar to that in the USA. In the United Kingdom, a similar case to the Daubert case came went before the courts.

Davie v Magitrates of Edinburgh.

Expert evidence lay before the court that the childís abnormalities were caused by the ingestion of the drug and that this ingestion was in the early weeks of the pregnancy before the doctor knew of it.

The court found that the doctor was liable through evaluation laid before the court to the effect that there was a factual link between the ingestion of the drug and damage to the nervous system in the first trimester of pregnancy. The learned judge acknowledged that this factual causation was not sufficient. Legal causation was needed, as well. It had to be shown that negligence on the part of the doctor had contributed materially to the harm suffered by the child. It was given as evidence that the taking of the drug during a critical state in pregnancy is the cause of damage and this contributed materially to the harm. Thus, the doctor was liable.

Factual causation, as seen from the Davie case, is not enough to find the defendant liable. The test goes further and begs the question of legal causation. One must establish whether the agent has materially contributed to the harm suffered. This goes back to the epidemiologistís value in proving causation. The epidemiologist will show the court that the probability that the consequence flows from the agent is higher than normal. This is translated, for the layman, into the phrase that there was a material contribution to the harm suffered.

CAUSATION AND VACCINES

Analogous to the proving of causation in the administration of pregnancy drugs is the administration of child vaccines and harm flowing therefrom.

In England, in the case of Bonthrone after a dose of DTP, a child went into spasm. When discharged from hospital, the child was suffering from brain damage and his brain had deteriorated.

Expert evidence was used to show that there was negligence on the part of the medics. How expert evidence proved this is in this case very factual. It was given in evidence that if there were any reaction to the DTP vaccine, it would manifest in six days of administration.

This can be compared to the position in Canada, in the case of Rothwell v Raes where abnormalities were again suffered after immunisation. Again this was a suit based on negligence. Here, the burden of proof was laid on the plaintiff to establish that the vaccine caused the damage.

Expert evidence in casu persuaded the judge that the vaccine did not cause serious permanent brain damage. Evidence further confirmed that if the vaccine did cause brain damage, it did not contribute materially ñ and the childís neurological disabilities from the start were a huge contributory factor. A clearly legal test to prove causation.

This same test of the harm being in close proximity was used in the Republic of Ireland in the case of Best v Wellcome Foundation that led the court to find that there had been negligence on the part of the manufacturer.

This highlights the fact expert evidence can be used in light of the adequate cause test of causation. Clearly, in the Rothwell case, the fact that the child already did suffer some abnormalities served to break what would be a tightly binding chain of causation by casting a shadow of doubt on the proximity of the agent and the subsequent harm suffered.

The approach ñ and thus the use of expert evidence to prove causation ñ in American jurisprudence is somewhat slack, with a "relaxed criteria" for assessing causation. This is particularly apparent in the case study of the Swine Flu Vaccine. Here, the task of the expert witness in proving causation would be simpler than the expert witness in Ireland or England for example. The courts in America, with particular reference to flu vaccines have adopted the stance criticised by most expert witnesses in the epidemiological field that association is not causation. Evidence given by the expert to the effect of there being a temporal association was held to be sufficient to conclude causation, though this was limited to cases where it could be shown that there was a link (though somewhat hazy) between the vaccination and the adverse effect, a viral syndrome called GBS. The US Government went further to codify this almost no-fault liability, compensating plaintiffs for injuries occurring within ten weeks of the administration of the drug.

It is interesting to note that probability testing and the ruling out of other causes of consequences that flow from the agent are mirror images of how applicable the different tests of causation are to the individual case before the court.

However, as Burchell and Milton re-iterate, a preliminary enquiry is made by means of the factual test. Yet, in terms of liability, one needs to go further and prove legal causation. There must be proof of a material contribution to the harm. From the discussion above, expert evidence comes to the forefront in assisting the courts n proving material contribution to harm, though it sometimes does so in a numerical and statistical manner.

TOXICOLOGY

Toxicology can be defined as, "the examination of clinical specimens, with the help of specialised apparatus and techniques, to identify and quantify substances and poisons not normally found in the body."

Toxicology examinations can disclose the presence of drugs or poisons in biological specimens. The examinations can determine the circumstances surrounding drug- or poison-related homicides, suicides, or accidents

When unnatural substances, such as a poison, enters a body this causes harm to the natural functioning of the body and may result in death. The use of forensic toxicology enables one to determine toxic effects and assists in interpreting analytical data. The assistance of a toxicologist in court can help prove causation through the determination of how much of an effect the poison has and its degree of contribution to the harm that ensues. Most of the evidence submitted by the toxicologist to prove causation is done through scientific standards of proof and toxic poisons discovered through the post-mortem.

Since the area of toxicology is so broad in its scope, for the purposes of this essay a more general overview of the role of an expert witness will be presented.

Anderson vs. PG&E

This well known case in the United States of America was made into the movie "Erin Brokovich". The case involved the solo investigation of one woman ñ Erin Brokovich who discovered that the health of countless people who lived in and around Hinkley, California in the 1960ís, 70ís and 80ís had been devastated by exposure to toxic Chromium 6 over 56 years. The Chromium 6 had leaked into the groundwater from the nearby Pacific Gas and Electric Companyís Compressor Station. What ensued was the largest direct class action lawsuit spearheaded by Erin Brokovich and Ed Masry. The giant utility was ordered to make the largest legal settlement in U.S. history, paying out some $333 million in damages to more than 600 Hinkley residents. 

The expert witness gave evidence to the effect that the chromium 6 which had leaked into the water supplies was highly toxic and carcinogenic. Looking at causation here, there was seen to be a direct link (the evidence strongly suggested that there was a factual link) to the poisoning of the water supply with the town residents who had been healthy to now developing cancer, respiratory and other diseases. The settlement was therefore justified.

Callahan v. Cardinal Glennon Hosp., 863 S.W.2d 852 (Mo. 1993)

A perfectly normal, healthy child was given a polio vaccine. The child remained in good health until a red area was noticed between the anus and scrotum where an abscess had developed. The child was given Tylenol and told that the abscess would go away. The complainant became paralysed and the hospital was sued for negligence. What had to be proved was a causal link between the doctorís actions and the resulting paralysis.

Causation here was proved through the examination of the actions of the St. Louis University and Cardinal Glennon hospital. A toxicologist submitted a testimony to the effect that the abscess contained certain bacteria (endotoxins destroying the immune system)

Here the "but for" causation test was investigated. Applying this test, it can be shown how expert evidence was used to prove this type of causation. Relying on sound "scientific knowledge", it was held that the practitionerís conduct would meet the "but for" causation test and would be a contributing cause to Danny's paralytic polio. In this case the traditional causation requirements were met.

Executor of the Estate of Stephen Brown v. Honeywell Corporation

In this American case of industrial poisoning, the deceased, Stephen Brown, had developed cancer, which was alleged to have its source in exposure to asbestos in the linings of the equipment, which he operated in the course of his work. The company argued that he had only been exposed to this for six months and this was an insufficient period of exposure to conclude causation. With the use of pathologists and toxicologists, the plaintiff was able to show that the six months exposure was sufficiently proximate to cancerous growths. This was done through the use of risk analysis that the toxicologist delivered to help the court establish what a relatively low risk to asbestos would cause, compared to high levels of exposure.

D. SOUTH AFRICAN PERSPECTIVE

The field of expert evidence in South Africa is not as developed as it is overseas. Expert evidence may be used in cases, but the use of the expert witness is not apparent at first glance. However, as in comparative law, the expert witness can be used to prove causation in both civil and criminal cases.

CIVIL CASES

In the case of Van Eck v Santam Insurance Co. Ltd expert evidence was used to prove causation on a claim for damages in a vehicle accident. The expert witness used accident reconstruction to prove causation. Whilst the learned judge said that such evidence cannot be given the same weight as the testimony of the eye-witness, it was used to corroborate the testimony of these witnesses and went a long way in proving the merits of the case and that whilst there was a factual causal link between the negligence of one Ms Viljoen, the award of damages was reduced due to negligence of both parties.

The case of Clarke v Hurst NO is a well-known case on the question of euthanasia. In Clarkeís case, it was difficult to ascertain whether his debilitated state had reached the limit where any further conduct could be recognised in law as having a causal effect. The testimony of a neurologist w as used to establish that there would be no causal link between the wife stopping the naso-gastric feeding of her husband and his subsequent death, and thus, she would not be acting unlawfully.

The learned judge in International Shipping Co. (Pty) Ltd v Bentley pointed out that in the law of delict, causation involves two separate enquiries.

Firstly, the enquiry is a factual one. Then the enquiry is legal in nature. It is generally very simple to draw factual conclusions in most civil cases. For example, in the Van Each case where ordinary witness testimonies can be used to see from the factual evidence tendered that there was negligence on both parts. But one must remember that the test is a causa sina qua non test. Yet, demonstrating that the wrongful act was a causa sina qua non of the loss does not immediately relate to legal liability. For legal causation to be established, the act must be linked sufficiently closely to the loss.

The linkage to loss is the area in which the expert witness operates to convince the courts that there is (or is not) sufficient proof to link the wrongful act to the loss.

CRIMINAL CASES

From the introduction, of this essay, the case of S v Mokgethi is given as an example of the role of expert evidence in the proof of causation. Similar to this case is that of S v Ramosunya where the appellant was convicted of murdering the deceased who he stabbed four times. The deceased was treated at hospital and discharged. A day later, the deceased died. A doctor who performed the autopsy gave evidence to the effect that the deceased had died from sepsis of the lungs, which could have a number of causes. There was no real basis upon which to conclude that the stab wounds had caused the death. At the same time, one could not rule out the possibility of negligence on the part of the hospital that treated him. Further, the sepsis on the lungs could have a natural cause.

This case echoes what has already been uttered in this essay that the judge is a man ñ or woman ñ who is knowledgeable in the field of law. When legal cases come before a court which touch on the need for medical knowledge, then the judge is a little out of his league and requires the help of experts in the field to assist in proving causation and making certain issues clearer.

An interesting case on the role of expert testimony on causation is the case of S v Williams where it was submitted by the defence that the disconnection of a respirator was sufficient to constitute a novus actus intervenes to break the chain of legal causation. However, medical evidence w as used to rebut this by showing that brainstem death had already occurred when the respirator was turned off. The act of the doctor did not constitute a novus actus, but the end of an attempt to ward off the consequence of the accusedís actions.

Psychological causation is harder to prove in general. If one examines the case has Ex Parte Minister Van Justice: in re S v Grotjohn the facts are such that there is both physical and psychological contribution to the death. In this case, no evidence is given of the calling of an expert witness. How eve, had one been called, the role of the witness would have been to show that the conduct of the deceased (killing themselves) was not far from the conduct of the accused. The accusedís conduct must not be so incapacitating at the time of death of the deceased. For example, in casu, the accused was having an affair, as his disabled wife did not allow him his "marital privileges". Bending the facts a bit to include a hypothetical situation where the accused played no physical role in the death of the deceased (here, he handed her a gun), a psychologist could be brought in to show that this mental torture is or is not in close proximity to the deceased killing themselves.

The above are examples from a South African perspective as to what the role of expert evidence is in proving causation. The reader will notice that inn South Africa the role of expert evidence in the courtroom to prove causation is identical to that in other studied parts of the world. Factual causation is easy enough for the judge to con clude. Legal causation and proximity testing often proves difficult ñ and the testimony of an expert in a certain field can clear issues up and help the courts in reaching a decision based on thorough studies and testing.

E. CONCLUSION

In the modern world, expert evidence has come to play an increasingly important role in determining a causal link between conduct and the harm suffered. The proof of causation in civil cases will have a large impact on the awarding of damages and therefore, expert evidence will generally be given great weight. In delictual claims (for example, claims based on medical negligence) expert testimony can be used to show that there is no sound basis upon which the plaintiff founds his claim. The evidence plays a role in setting up a defence.

In criminal cases, from the study given above, the importance of establishing a causal link echoes through in the aspect of charging a suspect and the subsequent sentence he shall receive for his unlawful actions.

Expert Evidence, as depicted from our essay can be of a highly scientific nature, depending on the particular field. This essay has, thus, tried to provide the reader with a general understanding of the field in question in order to help the reader better understand how expert evidence in these fields fits in and how it is relevant to the issue of causation in civil and criminal matters.

When cases appear before the courts, which require scientific standards of proof, the layman and the judge are often a little out of their depth. The expert evidence assists in clearing up hazy issues and establishing factual links and assisting the courts in confirming whether an act constitutes a novus actus intervens, as seen from the case of S v Williams. It must be noted, however, that it is up to the court itself, not the expert witness, to determine the answer to the issues in question.

F. REFERENCES

Cases Cited

  1. Anderson v PG&E - Superior Court for the County of San Bernardino, Barstow Division, File BCV 00300
  2. Barnett v Chelsea and Kensington Hospital [1969] 1QB 428
  3. Bendure v Kustom Signals No. C91-1173 ND Cal. 1993
  4. Best v Wellcome Foundations [1994] 5 Med. LR 81
  5. Bonthrone v Millan 1985 The Lancet 1137
  6. Clarke v Hurst NO 1992 (2) SA 676 (D)
  7. Daubert v. Merrell Dow Pharmaceuticals (92-102), 509 U.S. 579 (1993
  8. Daubert v. Merrell Dow Pharmaceuticals (92-102), 509 U.S. 579 (1993
  9. Davie v Magiatrates of Edinburgh 1953 SC 34
  10. Davie v Magiatrates of Edinburgh 1953 SC 34
  11. Ex Parte Minister Van Justisie : in re S v Grotjon 1970 (2) SA 355 (A)
  12. Executor of the Estate of Stephen Brown v. Honeywell Corporation Case No. 120595/00 New York Supreme Court
  13. Hockett v United States 730 F 2d 709 (1984)
  14. International Shipping Co. (Pty) Ltd v Bentley 1990 (1) SA 680 (A)
  15. Michael and another v Linksfield KS Park Clinic 2001 (3) SA 1188
  16. R v Loubser 1953 (2) PH H190 (W)
  17. Reynard v NEC Corporation 887 F. Supp. 1500 , 42 Fed R Evid. quoted in Carson
  18. Rothwell v Raes (1989) 54 DLR (4TH) 193
  19. S v Ramosunya 2000 (2) SASV 257
  20. S v Williams 1986 (4) SA 1188 (A)
  21. Van Eck v Santam Insurance Co Ltd 1996 (4) SA 1227

Articles and Books

  • Author unknown, Causation in medical malpractice cases
  • Bailey L et al "Reference Guide on Epidemiology"
  • Benecke M A Brief History of Forensic Entomology (2001) Forensic Science International Vol. 120, p. 2-14
  • Benecke M and Lessig R Child neglect and forensic entomology Forensic Science International 120 (2001) 155-159
  • Burchell and Milton Principles of Criminal Law 2000 Juta: Cape Town
  • Erdreich, L "Using Epidimiology to Explain Disease Causation to Judges and Juries" in Carson D " Professionals and the Court: A Handbook for Expert Witnesses"
  • Goldberg R Causation and Risk in the Law of Torts: Scientific Evidence and Medicinal Product Liability
  • Jones AJ Medical Negligence 1991 Sweet and Maxell: London
  • Lamm, S "The Epidemiological Assessment of the Safety and Efficacy of Bendectin" 21 March 2002
  • Mendelson, G Forensic Psychiatry: The Civil Practice
  • Morten Stærkeby Introduction to Forensic Entomology21 March 2002
  • Snyman Criminal Law (1995)
  • US Department of Justice Handbook of Forensic Services: Evidence ExaminationsóToxicology at 23 March 2002
  • Van der Westhuizen, J Forensic Criminalistics (1996) Heinemann: Johannesburg
  • Wager B The Testimony of Bugs ñ Forensic Entomology 22 March 2002

Internet presentation by Mark Benecke


(c) 2002 by Kevin Barnard*, Nichola Gray and Earl Hodges


Dr. rer. medic. Mark Benecke · Diplombiologe (verliehen in Deutschland) · Öffentlich bestellter und vereidigter Sachverständiger für kriminaltechnische Sicherung, Untersuchung u. Auswertung von biologischen Spuren (IHK Köln) · Landsberg-Str. 16, 50678 Köln, Deutschland, E-Mail: forensic@benecke.com · www.benecke.com · Umsatzsteueridentifikationsnummer: ID: DE212749258 · Aufsichtsbehörde: Industrie- und Handelskammer zu Köln, Unter Sachsenhausen 10-26, 50667 Köln, Deutschland · Fallbearbeitung und Termine nur auf echtem Papier. Absprachen per E-mail sind nur vorläufige Gedanken und nicht bindend. 🗺 Dr. Mark Benecke, M. Sc., Ph.D. · Certified & Sworn In Forensic Biologist · International Forensic Research & Consulting · Postfach 250411 · 50520 Cologne · Germany · Text SMS in criminalistic emergencies (never call me): +49.171.177.1273 · Anonymous calls & suppressed numbers will never be answered. · Dies ist eine Notfall-Nummer für SMS in aktuellen, kriminalistischen Notfällen). · Rufen Sie niemals an. · If it is not an actual emergency, send an e-mail. · If it is an actual emergency, send a text message (SMS) · Never call. · Facebook Fan Site · Benecke Homepage · Instagram Fan Page · Datenschutz-Erklärung · Impressum · Archive Page · Kein Kontakt über soziale Netzwerke. · Never contact me via social networks since I never read messages & comments there.