Market Thinking

making sense of the narrative

Big Data….available but not being used (yet).


As I sit here in my ‘bijou’ residence at Hong Kong airport for my ninth day of ‘totally necessary and not at all pointless’ Quarantine, (TNANAAPQ) with nothing to do but write blogs (!), I am interrupted by a knock on the door. It isn’t the usual thrice-daily tap from the hazmat-suited worker who has dropped a plastic bag full of food (a combination of meat, rice, vegetables and a sticky drink) on the chair outside the door for the inmates (Service!), rather it is a couple of testing staff – also in full PPE. It’s my day 9 test! The thrill!

The procedure is suitably hilarious. I have to sit on my chair, just inside the doorway, with my rubbish bit suitably positioned next to me. The PPE person then proceeds to go through the usual up the nose and down the throat procedure before disposing of their gloves into my waste bin. All the while some bizarre looking machine with pipes coming out of it whirrs away, presumably sucking away the evil airborne particles I am transmitting through having taken off my mask. Then they are off.

Not really a lot of difference – except their doors are open

This is the second of these tests I have had at the door of my cell deluxe room here at the Regal Airport Hotel since I arrived and is the only time I have seen anybody since last week. I have one more to do before I am released into the community. Before the latest two PCRs, I have also done a spit test on day 2 and of course the first PCR test when I actually landed. Prior to that I had to do a PCR test in Germany before I took off and a Lateral Flow test to fly from Italy to Germany the day before that. It probably goes without saying that I am also double vaccinated (and have had Covid). For those unaware of the exciting details of Hong Kong’s Covid restrictions, I had previously intended to fly from Italy to Hong Kong via Paris, but mid August they suddenly decided that France, along with the UK, Switzerland, Spain and the Middle East (basically anywhere with a direct flight to HK except Frankfurt) would now require three weeks of TNANAAPQ instead of two. Along with many others I decided that the cost of switching flights was worth the extra week of ‘freedom’.

The point of this is not to moan about my situation- there are many I know far worse off, especially those having to do this with small children – but to ask out loud what is being done with all this data? They must have literally millions of data points from when they began testing on arrival last year. I did quarantine twice last year – when it was still at home rather than costing thousands of pounds to stay in a hotel you would never otherwise look twice at – as did many others and it occurs to me that the HK authorities must have the data showing the probability of someone who tests negative on arrival subsequently developing Covid during the quarantine period. It won’t be zero, but statistically I would be willing to bet that it is close enough to make no difference. Or perhaps not, but surely making the data available should help us all understand more about how it spreads?

Even more so now. They now have data for people with two vaccines who have been tested not just on arrival, but multiple times in controlled conditions. On my count, by the time I am allowed out, I will have been tested on the 6th, 8th, 9th, 11th, 13th, 17th, 20th, 24th and 27th of September (the last two I have to organise myself but face serious consequences if I don’t turn up). That is nine tests in a month, six in a row negative so far. It all made me think, “how many people change sign on the tests over that period?”

As some sort of a start we might perhaps be able to investigate further from the data in this tweet, which was coincidentally sent to me via a colleague just as I was writing this (the universe works in strange ways).

I can’t verify that particular dataset, but let us for now presume it is correct. Meanwhile I can also only get data for June and July for the number of arrivals – suffice to say it is running at about 1% of the levels this time a year ago, itself an indication of the devastating effect on the local economy – but for the two months it is apparently around 14,866 – most of which is from the mainland. So let’s say that there have been 20,000 international arrivals in the last three months covered by the data in the tweet, of which the ex-post need for paid-for hotel quarantine (justified by a subsequent positive test) totaled 87, or 0.4% of arrivals. However, given the acknowledged false positive rate for PCR tests of between 0.4% and 0.9%, it is entirely possible that all, as in every single one, of the positive tests in Quarantine was actually a false positive.

For the avoidance of confusion, on the same basis, the number of cases between day 7 and day 19 that tested positive and thus justify a two week or even a three week quarantine was..3. That is 0.015% of arrivals.

To repeat, this is not to complain, I chose to come back to Hong Kong (I have a business to run) and all the Hong Kong people I have encountered thus far have been perfectly sweet and charming, rather it is to suggest that with probably one of the best datasets anywhere in the world Hong Kong uses the information gathered (at some considerable cost to all concerned) to better inform the Health Authorities of the world about how this virus may (or may not) spread. Got to keep thinking positively!

Meanwhile, I have my instructions.

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