When faced with the unknown, we form assumptions based on what we know from previous experience. In science, it is fancier to call those assumptions as hypotheses. And hypotheses are meant to be tested. Those whom have done sufficient level of statistics will quickly understand this as hypothesis testing and at the very basic level, this is the philosophical foundation of whatever Covid-19 testing that exist out there.
The logical set-up is simple. There is a null hypothesis that a test seeks to reject. A failure to reject based on some benchmark means the hypothesis may have some truth to it, while a rejection means the alternative hypothesis is likely true. In the case of Covid-19 test, the null hypothesis would be “the person is heathy” and the alternative hypothesis would be “the person is unhealthy.”
Notice the use of ‘may’ and ‘likely.’ It expresses possibility. It reflects an element behind any statistical testing method: confidence. Confidence is an important factor because all testing are prone to error. We try to reduce it, but there is a minimum error level we have to tolerate. The errors come in two forms: it is possible to test a healthy person as unhealthy, and as we have witnessed in the past several weeks in Malaysia, it is also possible to test an unhealthy person as healthy.
When we tested a healthy person as unhealthy, that is known as a Type I error. Here, we rejected the null hypothesis when we should not. It is a false positive. As far as Covid-19 is concerned, this is an inconvenience to the person tested falsely. There will be cost involved, but the person will very likely be fine.
When we tested an unhealthy person as healthy, that is Type II error. Here we failed to reject the null hypothesis when we should. It is a false negative. In our Covid-19 context, this has a life-threatening consequence.
Between the two errors, a false negative is clearly the worse mistake to commit.
This is why adhering to strict and fulltime quarantine is important. Based on what we know from public health professionals, 14 days is the reasonable period for a quarantine. Centers for Disease Control and Prevention in the United States for instance stated that any symptom would manifest itself between 2 to 14 days. If we are truly sick, regardless of test results, there is a very high likelihood the truth will be discovered.
In Malaysia, we have ignored the risk of Type II error so that the ruling class could get their convenience. After violating safety and health procedures regarding social interactions during a time of pandemic, too many Malaysians—the politician class generally, the ruling class particularly—were just too happy to rely on testing to determine whether we are free of Covid-19, without understanding the underlying risk.
Worse, the authority was just too happy to short-circuit the process as if there is no error in testing. Whether the local health authority was strong-armed into it, we do not know. What we know is that quarantine time for those coming from high-risk areas in Sabah was 3 days, and not 14 days. Unlike the 14-day period, there is no scientific explanation why 3-day period were appropriate. In fact, a 3-day quarantine period is inconsistent to what we have been informed by health authority about the nature of Covid-19.
Because of the complete ignorant trust in testing method and failure to understand the risk of Type II error by a group of people—ministers no less—we Malaysians now have to suffer a pandemic wave bigger than we had earlier.
We all have sacrificed to fight Covid-19. We went through a severe lockdown. We worked from home. We stopped going out. We wore mask however uncomfortable the experience was. We were successful in flattening the curve, until the selfish men and women undid our success.
These ignorant, arrogant men and women have triggered a type II error crisis in Malaysia. They all should resign to atone for their sins.