28 October 2016
Residents of Kai Ching Estate collect water from newly installed water pipes amid the lead contamination scandal. Photo: HKEJ
Residents of Kai Ching Estate collect water from newly installed water pipes amid the lead contamination scandal. Photo: HKEJ

Why govt lead contamination experts are untrustworthy

Hong Kong was once a society that held experts and specialists in high regard and relied heavily on their professional opinions.

Whenever there was a crisis in public affairs, the government would often seek advice from experts and ask them to propose solutions to the problems, and most of the time the public would settle down afterwards.

However, the opinions given by government experts on the recent lead contamination scandal have drawn widespread criticism from the public, and some even suspect that these experts are trying to downplay the crisis and cover up for the government.

So as average citizens, how should we treat the so-called authoritative opinions from experts? Perhaps we can look at how our court of law treats expert testimony.

The court often has to deal with cases in which the facts and details are beyond the scope of the knowledge and expertise of the judges themselves, and in those cases the court has to summon expert witnesses to testify during trials and give their professional opinions.

However, since common law courts adopt the adversarial system, the plaintiffs and the defendants may often summon their own experts. As a result, the court often has to handle conflicting opinions from experts summoned by both sides, and decide which of them are believable.

As time passes, the common law court has gradually developed a set of guidelines and standards based on which judges can evaluate the probative value of the opinions of the experts testifying before the court.

The standards against which expert’s testimonies are assessed are as follows: 1. Whether the expert’s testimony is consistent with other evidence presented in the trial; 2. Whether the inferential process through which the expert’s opinions are formed is rigorous and consistent, and whether it can apply to other similar circumstances; 3. Whether the hypothesis based on which the expert’s opinions are formed is reliable and applicable to the particular circumstances in the case; and 4. Whether the investigation procedures carried out by that expert is thorough and free of negligence.

The resume, professional experience, reputation and the impartiality of the experts are also taken into account by the judge when determining whether their opinions can be accepted.

After having a glimpse of how expert’s opinions are treated and evaluated in court trials, perhaps it is not difficult for us to identify some of the fundamental flaws in the opinions given by some of the so-called experts over the recent lead contamination scandal.

For example, specialists from the Water Supplies Department have said the tap should be left running for five minutes before collecting the water sample for lead level test in order to get accurate results.

The problem is, however, how many households are actually using their water in this way on a daily basis? It doesn’t take any expert to figure out that it is very rare that anybody would let their tap run for five minutes before using the water for cooking and drinking.

Apparently, the opinions given by experts of the Water Supplies Department in this case are clearly out of touch with reality.

Another example is that following the exposure of the contamination, blood test results indicated that some children have excessive level of lead in their blood, and a toxicological specialist from the Health Department said that children can in fact absorb lead into their blood from multiple sources, such as from biting pencils.

His remarks immediately came under fire and some even called him ignorant since it’s been a long time since manufacturers of pencils stopped using lead in their products.

Then came another expert, who debated with a lawmaker during an RTHK show over whether it was appropriate to collect “overnight water” sample for lead level tests. This expert went on to say that consuming water that contained less than 10 micrograms of lead would not have any adverse effect on a person’s health, unless he or she kept drinking it for 70 consecutive years.

His words again drew criticism since he is in fact an engineer specializing in pipes, and it is obviously not within his specialty to determine how long a person has to drink lead-contaminated water before it will cause permanent damage to his health.

In an era when even an average individual can have access to a wide range of information through the internet, the opinions and advice of experts are no longer unchallengeable.

Even the most authoritative experts have to present their opinions in a logical and consistent manner in order to convince the public, because members of our public have become so aware of their rights that they would no longer allow themselves to be patronized, not even by seasoned professionals.

This article first appeared in the Hong Kong Economic Journal on July 28

Translation by Alan Lee

[Chinese version 中文版]

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