Covid Policies and Continued Testing (Addended; updated 22dec21)

George Rebane

Governments here in America and around the world are fumbling around with Covid response policies as every new variant is discovered and infection cases surge and retreat.  People continue to be assured that the public agencies and their political leaders are “following the science”, even when there is no evidence of such following presented or demonstrated.  But as we have all experienced, the government agencies, ‘experts’, and politicians are all over the place with their advice, prescriptions, and mandates.  It is clear that neither the national nor global collective knows how to properly respond to the pandemic (e.g. here)  More disturbing are the ongoing subterfuges that leak out in the media and online.  An extremely revealing and disturbing interview is by Tucker Carlson of Robert Kennedy Jr, author of the current best seller The Real Anthony Fauci (2021).  It has been pulled by YouTube and FN, but is still available on Bitchute here.

In my many-years experience with healthcare decision making, I have found that practitioners in the medical industry are profoundly ignorant of uncertainty, risk, utility, estimation, and in general critical interventions that are affected by uncertainties (i.e. depend on probabilistics).  This assessment applies especially to the physicians with whom the patient interacts.  These people are uniformly condescending or arrogantly hubristic in how they hide their ignorance of the maladies in question, and what is required for the lay patient to make a reasoned and understandable decision.

Perfidy aside, nowhere is such practice more visible to the technically trained than in the field of public health.  A current posterchild demonstrating this is how little and erroneously we are informed about Covid testing.  We are told that testing is somehow critical to reducing the spread of the disease – the more testing the better.  Tests are communicated to the layman as consisting of one uniform process that somehow reliably determines your infection status AND your ability to infect others.  Science tells us nothing could be further from the truth.

Ignorance of causes and effects should be usefully represented quantitatively.  Such ignorance is no excuse for avoiding quantitative decision support techniques.  For example, here is an AMA article that talks about test types, dependers, and whyfors, but gives you no information about the involved probabilistics (e.g test sensitivities and specificities) for decision making.  Today machines can be designed to incorporate more knowledge than any one or group of practitioners can manage in literally any specific domain of expertise.  As a consequence, where such technology is applied, AI-based decision support systems outperform their human counterparts every time – and this is specifically the case in medicine and healthcare.  Here is Nobelist Daniel Kahneman on AI bettering human decisions. (here and here)

To illustrate the spread of our collective ignorance and hysteria, I want to return to a robust example from Covid testing.  In these pages I’ve devoted a lot of time and real estate to presenting the quantitative factors that relate to Covid test results, and their impact on the utility of such testing.  Testing is usually performed for two reasons – to measure the spread or penetration of a disease in a target population, and to determine whether a specific individual has been infected.  Recall that no test is perfect, and the reliability of a medical test is given by its sensitivity (probability that the test comes back positive when you do have the disease), and specificity (probability that the test comes back negative when you don’t have the disease).  Last year I posted ‘Testing, testing, testing – Really?’ which contained the following example.

(Recall that the minus sign with the hangy-down part, like this ¬, means ‘not’.  So ¬TP means ‘not Test Positive’ or simply a negative test result.  Similarly for ¬V, which means ‘not virus’ or not infected.)

We start with the prior probability that the asymptomatic walk-in has the virus which computes to about P(V) = 100K/330M = 0.0003 assuming generously that today about 100K Americans have been infected as opposed to today’s reported number of 42K.  The test’s likelihood ratio L(TP|V) = P(TP|V)/ P(TP|¬V) where V stands for virus present, ¬V means virus absent, and TP indicates Test Positive.  So the ratio is simply the two probabilities of a positive test given that the virus is present and the virus is absent – i.e. ¬V.  What we want to calculate is the updated or posterior probability that a person has the virus given that the test came back positive.  The Bayes formula for that is P(V|TP) = L(TP|V)P(V)/[L(TP|V)P(V) + 1 – P(V)].  Using the published numbers P(TP|V) = 0.60, and P(TP|¬V) = 0.25 (rough average of quoted range), we get L = 2.40.  Plugging this into the Bayes formula gives us

P(V|TP) = (2.4)*(0.0003)/[ (2.4)*(0.0003) + 1 – 0.0003] = 0.00072.

This tells us that an asymptomatic walk-in testing positive more than doubles his probability of having been infected, but his overall probability of actually being infected is still ridiculously low.  So what are you as a medical professional going to do with that information?  The answer is nothing much, because his probability of being uninfected, even with testing positive, is still P(¬V|TP) = 1 - P(V|TP) = 1 – 0.00072 = 0.9993, almost certainly virus free.

Now what happens when the test comes back negative; what’s the probability P(¬V|¬TP) that individual is actually not infected.  Sparing you the math, the answer is P(¬V|¬TP) = 0.9998, or almost certain that the individual is not infected.  So now you have two almost certain probabilities (0.9993 and 0.9998) that there is no infection present regardless of whether the test came back positive or negative.  That is the dirty little secret that no one wants to tell the public, because it reinforces the naked truth that the objective here is control and not ‘following the science’.

I dug up some current data on antigen tests for Covid.  The cited antigen test parameter ranges are - sensitivities P(TP|V): 37.7%-99.2%, specificities P(¬TP|¬V): 92.4%-100% (here).

If we also include the averages of these data and compute the chances that any given walk-in has Covid, regardless of their test’s outcome, then we can summarize these in the table below.  Clearly it demonstrates the futility of using single test outcomes to make healthcare decisions for the tested.

From the above table, note that even with the almost ‘perfect’ (rightmost) test, we can conclude that a positive test result yields little more than one-in-five chance that the walk-in has the virus.  The less perfect and more realistically performing tests yield extremely low probabilities of infection no matter the test result.

On the other hand, if we claim prior ignorance of infection for the tested, the results below show that again only the high-performance rightmost test gives reasonably reliable results.  The lesser performing positive test results may be of some use, but fail miserably when returning a negative result.  If we can make a case that each test gives an independent result, then multiple tests may be of some use if their results concur.  But the bottom line of all such testing is that, at best, it only provides a marginally useful snapshot of the patient’s infection status which can change the moment exposure is resumed.

Having examined such results, which are not discussed in the MSM, the question still begged is revealing the real purpose of administering such tests for determining the public’s access to events, transportation, and schools.

For completeness, I list below some major RR commentaries and analyses of testing as applied to the current Covid pandemic.

‘The Value of Testing'

‘Testing- One mo’ tahme’

‘The Reliability Roulette of Testing’

‘Covid Testing – Unclear on the Concept’

‘The Real Value of Unreliable Tests and Testing’

‘Testing to determine population fractions’

[Addendum]  Absence of Covid symptoms decision trees is a very clear indication that the medical industry has no clear or unified idea as to how lay people should respond when they believe they have Covid-like symptoms or have been exposed to Covid.  Decision trees have been used to teach diagnostic processes in all fields, not only in medicine.  And they are the standard vehicle for capturing and communicating such diagnostic and ‘repair’ processes.  Decision trees are very machine programmable, and have been used in automated (e.g. 'expert') and interactive diagnostic and maintenance systems for decades.

The above figure shows a simple breast cancer screening decision tree.  Much more complex trees with multiple branches (higher arity) from every decision node are easy to construct once a (diagnostic or therapeutic) plan is adopted.  The fact that no such a tree has been published by NIH or CDC or AMA or … means that they really don’t know what they are doing in fashioning Covid response policies - they have no agreed upon coherent approach.  (More evidence that science does no speak with a single voice.)  Such trees can be used by everyone, including people of modest intellect, to decide whether they need further medical attention or just continue self-observation and apply available at-home therapeutics.  They can also be versioned, and new versions can be published as newer/better data becomes available and/or process knowledge is updated.

[22dec21 update]  Here is a Covid decision tree designed by the school nurse at the Bear Creek School in the Seattle area.  People understand the utility of these decision aids, and are starting to generate them for their own organizations.  This one is for two categories – vaccinated and unvaccinated – of students.  H/T to our daughter who works at Bear Creek School for sending this down.  Now if we could only get the CDC or NIH off their collective butts and publish such a tool for the general population, it would sure turn a lot of heat into light.

Comments

[scenes]

"Having examined such results, which are not discussed in the MSM, the question still begged is revealing the real purpose of administering such tests for determining the public’s access to events, transportation, and schools."

I suppose it's the same reason as requiring masks, even the poorly fitted non-filtering variety which are so common...or proof of 'vaccine', even though there's so much uncertainty as to whether it actually cuts the spreading rate.

I'm willing to accept that all the measures make some difference, but the lack of rigor in the analysis is stunning, especially given the huge knock-in effects of COVID worldwide. No surprise given the poor practices in many (most?) medical papers in terms of sample selections and size.

Hell, by now you'd think there's be *so much* available data on different groupings of humans that some data wrangler could inform us of really interesting relationships, no causalities even really needed. You can certainly argue that the design of policy is removed from medical professionals as I suspect that epidemiology can be presented as purely a problem in data and mathematics with the actual biological effects reduced to a series of rules of thumb.

[George Rebane]

scenes 712am - You're absolutely right Mr scenes. Epidemiology is a pure 'data and mathematics' problem in diffusion (over non-homogeneous surfaces). And sadly, it is not taught from that perspective, or with those tools.

[Mike Walker]

That's a long way of saying that doctors are not data analysts. The healing arts are art - Epidemiology, like stereotypes, is a function of distance. If you get into medical school and decide that being a doctor is too hard, you get into Public Health.

[George Rebane]

MikeW 1139am - And that's the point Mr Walker. Physicians deal in an arena of unreliability, but one in which (clinical) data abounds, and (relative frequency) probabilities can be computed on everything imaginable. They are paid to play the odds correctly in their diagnoses and therapeutics, and it is exactly the odds about which they are dismally ignorant and hubristic. That ignorance contributes to the 200K+ people who die annually from 'medical mistakes'. Physicians are NOT artists any more than is your car mechanic or computer technician. But the overwhelming share of them happened to be stunted in numeracy - they practice with a multitude of memorized rules of thumb (technically 'heuristics'), rules which many of them forget and which change with alarming regularity. Machines will soon dominate this field to the benefit of all. And how they got themselves the honorific 'Doctor' is another story. More here -
https://rebaneruminations.typepad.com/rebanes_ruminations/2020/12/is-there-a-drdoctor-in-the-house.html

[Barry Pruett]

Rhetorical question: If omicron is spreading like wildfire and will be a COVID blizzard and if nobody is dying from omicron, who cares? I mean of course I don’t want any one to get sick but if you have the mild symptoms of omicron and you highly, highly likely not going to die, what’s the problem?

[George Rebane]

BarryP 312pm - (Rhetorical answer) Exactly, the problem has not been identified. The only bad thing about Omicron is its virulence, but not its impact on the infected. So the latter part is not emphasized, but the former is for the purpose of more control, mandates, and manipulation by politicians and bureaucrats. The average snuffy is not smart enough to even question the effect of contracting Omicron on the various demographic groups; all they're told to focus on is that "it's spreading four times as fast."

[scenes]

" they practice with a multitude of memorized rules of thumb "

I'm always kind of surprised how much of a periodic exam (for someone without an obvious problem) consists of, how do you feel?, how much do you weigh?, what is your blood pressure? what is your O2 level? (this last because of readily available gizmos in later years).

Honestly, if you feel fine and can measure these last three with cheap devices, just what is the point?

I'm reminded of Taleb's chart as he was charting blood pressure vs. his exercise routine.

https://twitter.com/nntaleb/status/1445884202373636097

Given those values (reasonably sampled I think), of what possible use is a doctor's office blood pressure reading?

[Mike Walker]

It's Wildfire ! It's A Blizzard ! It's Americron - God's Vaccine !
It's MAGA Country !

[Gregory]

It's Lrrr, Ruler of Omicron Persei 8!

The $20 pulse ox device is an amazing device... the Nonin onyx (?) was $400 20 years ago... am guessing a patent ran out in the meantime. When my first wife was dying of cancer and on O2... I tried to get her oncologist to prescribe one, but no luck. All of the nurses had them.

Now I've a $20 'smart watch' and it incorporates a pulse oxymeter. Tells good time, too.

[Gregory]

Omicron, if it is a mild version of the Alpha and Delta, may be what we used to call a "vaccine".
Scary.

[scenes]

"Now I've a $20 'smart watch' and it incorporates a pulse oxymeter. Tells good time, too. "

It's a bummer that so many of those products have a strong surveillance marketing angle to them, I can imagine the end game to that.

Once they crack the measurement-analogous-to-blood-pressure problem (have they? I haven't run into it) they'll really have something. Gather up a month's worth of data, back end software summarizes some angles to heart health pretty well. Maybe we'll see home ultrasound machines.

The war between the doctors' unions and those providing the ability to do diagnosis at home should be interesting. I need to look into how the 23andMe situation panned out. Next up, the Google Smart Toilet(tm) which announces your proclivities to insurance companies and local law enforcement.

[Gregory]

The thing would quickly run down if it was on continuously, but yes, I am concerned about the privacy angle. Especially since the company's beach head in Washington state is obviously secondary to the company in (drum roll, please)... China.

[Scott O]

Not sure if everyone has seen this:
https://www.powerlineblog.com/archives/2021/12/the-collins-crock.php
I'm so glad the govt and big social media work together to make sure only their version of sciency stuff gets aired in public.
It has worked with the AGW scam pretty well so far. let's just apply it across the board.

[Bill Tozer]

'The Corporate Media Freakout Over The Omicron Variant Isn’t Normal, It’s Psychotic'

https://thefederalist.com/2021/12/22/the-corporate-media-freakout-over-the-omicron-variant-isnt-normal-its-psychotic/

[Scott O]

BT 8:45 - Hilarious.
We boldly traveled through 6 states with no mask and are here in Tejas. Remember that this state is inundated daily with the unvaxed from the south per special permission from Biden. So, we fit right in.
What's a couple more, right?
I'll fill y'all in later on the misery and death that has been decreed for us'ns.
Once again, the stories I read about the national and international response compared to what I'm seeing driving around and shopping here in the Metro-Plex of the Dallas/Fort Worth area is astounding. It is as night and day.

[Barry Pruett]

From Ben Shapiro…

So once it became clear that covid was not in fact a pagan god visiting vengeance on the unwashed Trump voters alone, the media and Democrats are now willing to admit the following:

1. Cloth masks are ineffective against omicron (Leanna Wen, CNN);
2. The vaccinated can spread and get covid;
3. The death rate is comparable to the flu (Chris Hayes);
4. Many people are entering hospitals with covid, not from covid (Fauci);
5. Natural immunity is a reason omicron hasn't been as virulent (Fauci);
6. We have to take into account societal needs, not just spread prevention (CDC);
7. The asymptomatic should not be tested (NFL);
8. We should focus on hospitalizations and deaths, not case rate (Biden);
9. Children are not at risk and schools should remain open;
10. Covid is predominantly an illness affecting the immunocompromised and elderly and we should not shut down society.

Basically what sane people have been saying since May 2020, and mind you, all of this above was finally admitted to within one week. All of you liberals on the left side of the room, you are idiots and got played by the elites who picked your pockets passing trillions of stimulus that you will never see but will pay for in inflation. Freaking morons.

[Bill Tozer]

OMICRON DEATH!”
Matt Taibbi has posted an inspired account of “Omicron DEATH!” Matt Orfalea is responsible for the companion video (below). Taibbi concludes by calling for future Covid variants to be given Fangoria (“The World’s Best Horror and Cult Film Magazine Since 1979”) names: the “Mutilator” Variant, the “Suffocating Agony” variant, the “Shaft-Sagger,” the “Face-Eater,” etc., and asks: “Would you bet against something like that coming?” It might be best for you to hold off answering until you can check out Orfalea’s video.

https://www.powerlineblog.com/archives/2021/12/omicron-death.php