A thorough analysis of how mobile phone apps and location data are being used worldwide for attempts at Covid-19 tracking

The linked report is a very thorough analysis of what is being done in countries throughout the world in regards to cell phone data for Covid-19 tracking, and looks at a number of issues, particularly with regards to privacy.

Source: Mobile Location Data and Covid-19: Q&A | Human Rights Watch

I see so many problems – technology – both software and RF issues – usage scenarios, laws, privacy issues, and practical issues such as unenforceable quarantines via phone, false positives and insufficient participation and so on – that phone-based tracking apps will not provide meaningful benefits during the current calendar year.

Continue reading A thorough analysis of how mobile phone apps and location data are being used worldwide for attempts at Covid-19 tracking

Contact tracing apps do not track surface contacts across time


Contact Tracing of Surfaces Across Time

Another problem with contact tracing apps is they cannot detect contacts across time. Some one sits on a bus seat or commuter light rail seat, coughs. Then gets up and leaves. Another person boards and sits in that seat and touches it with their hands. The BLE model is unable to detect this contact. Considering that the NYC subway is now thought to have been a major vector for diseases transmission, this is a serious short coming.

Another example – some one sits at a table at Starbucks, coughs on the table a few times and then leaves. 3 minutes later, someone else sits at that table and touches their hands on the table and later scratches their nose. The contact tracing app cannot detect surface contamination scenarios across time. While Starbucks might clean tables frequently, there is no guarantee.

There is no way to solve this problem using a BLE contact algorithm that does not store actual location data – the BLE tracking app only detects instantaneous “moment in time” contacts.

This week the CDC said that may be surface contamination is not a big source of infections so perhaps this is no longer a big factor.

Does it Matter? May be not?

And then perhaps none of this matters. In Utah, where they have traced the source of most Covid-19 patients’ contacts, about 60% were traced to close family contacts that had the disease and about 25% to close social contacts. That’s 85% of all traced contacts. There were not many random connection contacts leading to becoming infected. Originally, China thought about 60% were due to random contacts – but it might be appropriate to extrapolate that – from congested cities where much of the population travels via public transit – to many U.S. states (like Utah) where public transit use may be just 1-2% of the population.

Moving Further Apart Can Increase Signal Strength!

Another interesting problem with BLE-based tracking apps. They rely on the BLE 1 mw discovery process which can send a signal out to about 10 meters. They combine this with the Received Signal Strength Indicator to estimate that a contact is within about 6-7 feet. In a pure “free space” environment, signal strength can approximate distance. But the real world is not a “free space” environment.

First, if the phone is in your left pocket and you stand several feet from another person on your right, whose phone is in their right pocket, the direct path may have lost 20 db of signal strength due to your body blockage. The software thinks the two of you are far apart when you are actually standing next to each other.

Second, in the real world, radio signals do not travel in a straight line from transmitter direct to receiver. Instead, signals reflect off of objects in the environment. Some times the reflected signals arrive at the receiver in a way that increases their apparent strength and in other cases they arrive in a way that decreases their apparent strength. This is known as “multi-path”.

Think of a pond of calm water. Toss in a rock and see how the waves move across the surface. What happens when the waves strike the shore or another rock – they typically reflect or bounce back creating a new wave front. In a complex environment, there are many wave fronts traversing that water. In some places, wave heights may combine momentarily to create a higher wave, while in others they may combine to create a deeper trough.

The effect of this in the Bluetooth contact tracing app scenario is that – and this has been tested in the real world – there are real scenarios where people moving further apart see a stronger received signal strength!

The software erroneously thinks these two people have increased their risk when they are moving further apart!.

The opposite can also occur – as people move closer together, due to multipath, the devices may sense a drop in signal strength and erroneously think there is less risk.

The Need for Controlled Trials

This is why this technology must be tested in the real world before it is rolled out to entire populations. The bottom line assessment is: Does it detect actual contacts we need to worry about – without missing contacts we do need to worry about?

The Gold Standard: Does it result in an actual, measured decrease in the spread of Covid-19 and a reduction in mortality?

To answer those questions requires controlled trials, just as controlled trials are required for the use of hydroxchloroquinine in the treatment of Covid-19.

Some will argue no controlled trial is necessary as the use of the app is harmless. However, if you are periodically placed in 14-day quarantines – unnecessarily – harming your income and mental health, is that truly harmless?

If not tested, deploying smart phone contact tracing apps is a mass population medical experiment without informed consent – which is illegal in the United States. But given we are dealing with public health, laws no longer matter, of course.

Privacy: The GDPR right to privacy in the EU

Two years ago, Europe introduced the world’s toughest data privacy legislation, putting on notice the tech giants of the world who’d grown fat off your personal data. The General Data Protection Regulation, widely known as the GDPR, is a far-reaching law designed to uphold the right to privacy for Europe’s citizens. It promises to issue bigger fines for data protection violations than have ever been seen before: 20 million euros, or up to 4% of a company’s annual worldwide revenue from the preceding financial year, whichever’s greater.

Source: As the GDPR turns 2, Big Tech should watch out for big sanctions – CNET

Why “Covid-Tracking Apps” will probably not work

I previously wrote about covid tracking apps and that what a “tracking app” is varies tremendously by country. Please read that first.

There is another issue that crops up – and that’s the effect of conditional probability (or Bayes’ Theorem). I am still reviewing this to see if I did something wrong (I think I did do some things wrong – see Afterwordthe idea is probably sound but the calculations may be wrong) – with reasonable assumptions, phone-based covid-19 contact detection apps seem unlikely to provide a benefit.

Singapore is the only country to have used a Bluetooth-based contact app so far. At the time of this writing, the U.K. is running a trial of BLE-based tracking apps.

Singapore achieved only a 12% participation rate. (Update: as of end of May it was up to 25%, which is still too small. Consequently, Singapore cancelled the smart-phone based contact tracing app).

Continue reading Why “Covid-Tracking Apps” will probably not work

University of California to drop the SAT and ACT testing requirement

Yes! This is a permanent elimination:

The University of California board of regents, in a landmark move that could reshape the college admissions process across the country, voted Thursday to drop the SAT and ACT testing requirement.

Source: UC regents unanimously approve plan to drop SAT and ACT from admissions – SFChronicle.com

My own state has also eliminated SAT and ACT tests for public college admissions, starting this fall.

As the victim of a GRE testing failure decades ago that shaped my entire life, I am thrilled to see the end of these absurd testing regimes.

Continue reading University of California to drop the SAT and ACT testing requirement

Does brain damage lead to people becoming “sudden geniuses”?

Don’t think it worked for me:

There’s mounting evidence that brain damage has the power to unlock extraordinary creative talents. What can this teach us about how geniuses are made?

Source: The Mystery of Why Some People Become Sudden Geniuses

Having had 5 mild TBI and one moderate TBI, it’s hard to think about this 🙂 Also, I do not recommend injuring your brain as an approach to becoming smarter.

While my life turned out well, many opportunities went missing due to dealing with gremlins of past brain injuries that were not diagnosed and treated until about 18 months ago.

Apple-Google Bluetooth “contact tracing app” depends on widespread adoption to be useful

The biggest challenge for these apps going forward is adoption. The more phones that opt-in to the system, the more successfully it can detect how the virus spreads. Apple and Google say that getting the public to trust the apps and opt-in is critical to the effort.

Source: Three states commit to Apple-Google technology for virus tracking apps

As I explain in detail here, the Apple-Google approach will unlikely have sufficient users to be particularly valuable. If 50% of all smart phone users install the tracking apps, we will have the potential to detect just 16% of close contacts. Is that sufficient to have an impact on the spread of Covid-19?

About 80% of adults have a smart phone. If we assume all 81% have phones capable of running the software (which is not realistic as many people continue to use older phones and may not have compatible Bluetooth Low Energy hardware), then 50% of all users means 40% of adults have the app installed.

The probability of a person having the app is then 0.4. The probability of a 2nd person you meet having the app is also 0.4. The probability that you and a random person you meet both have the app is 0.4 x 0.4 or 16%. Even if all 81% have the app installed, the probability of a detectable contact is at most .81 x .81 or about 65% of the adult population. This does not include children, lowering the contactable percent even more.

Most other countries that have used phone-based contact tracing – so far – have used network-based tracking, not app-based. In network-based tracking, the network tracks the location of all cellular phones – both smart phones and dumb phones with a 100% coverage/participation rate. These systems identify contacts within about a 100 meter radius, which is too broad. But these countries follow up with a robust public health in person contact tracing operation and offer Covid-19 tests so that people are not needlessly placed in 14-day quarantines.

As you can see, the Apple-Google model is unlikely to have sufficient usage to detect many contacts.

“Low code” app development surges amongst pandemic

The shift to remote work has led some companies to come up with quick digital solutions for tasks that have become hard to tackle during the coronavirus pandemic.

Source: Emptying Offices Prompt Adoption of Low-Code to Build Work Apps


“Low code” means using “drag and drop” tools to create software applications. These systems make the creation of user interfaces easy, and provide functionality through similar drag and drop interfaces. We used to call this “Rapid Application Development” or RAD.

I have long though future software would be created with advanced tools that simplify the development process, particularly for straight forward applications of modest size. MIT App Inventor, and Scratch, are examples of drag and drop programming interfaces. Scratch is for teaching programming concepts to children. App Inventor leverages the Scratch concept into developing mobile apps for Android. You can learn about Microsoft’s Power Apps feature here.

RCAF Snowbirds

In memory of Capt. Jenn Casey and the difficult times faced by the RCAF Snowirds right now. These photos taken at the Oregon International Airshow 2014, Hillsboro, Oregon.

I have been using a photo of the RCAF Snowbirds as the background on my Android tablet for a couple of years.

Electric Vehicle Efficiency

According to the U.S. government:

Energy efficient. EVs convert over 77% of the electrical energy from the grid to power at the wheels. Conventional gasoline vehicles only convert about 12%–30% of the energy stored in gasoline to power at the wheels.

Source: All-Electric Vehicles

Of course, one must also include the conversion of the original fuel source into electricity but that depends on the original fuel source: oil, natural gas, coal, nuclear power, hydro, geothermal, solar, wind and so on – and can vary widely.

Regardless, gasoline engines are not very energy efficient in terms of turning the energy in fuel into forward motion, as noted above and also noted here. EVs have a slightly different problem – while they use electricity efficiently, EVs weigh quite a bit more than a similar sized gasoline vehicle.