In many legal jurisdictions, Blackstone's ratio (also known as the Blackstone's formulation) is the idea that:
It is better that ten guilty persons escape than that one innocent suffer.
That is, false negatives (a guilty person is acquitted and goes unpunished) are far less adverse than false positives (an innocent person is convicted and suffers). This balance between false negatives and false positives sounds logical.
What if we apply Blackstone's ratio to contact tracing apps:
It is better that ten exposed persons not be notified than one incorrectly notified person suffer.
That is, false negatives (a potentially exposed person is not notified and goes on to infect other persons) are far less adverse than false positives (an incorrectly identified person is notified and tests negative to COVID-19). This balance between false negatives and false positives doesn’t sound logical and unfortunately this is how it’s playing out with some government contact tracing apps. The end result is more and more speed humps are being added to speedy remediation of disease outbreaks.
At this time there is a debate on how and where COVID-19 contact tracing data is managed. At the heart of this debate is user privacy and the fear of government mass surveillance. However, all parties in this debate agree on the need for a contact tracing app to aid contact tracing investigators quickly identify potentially exposed persons who may have been in contact with a diagnosed carrier in order to contain and suppress disease outbreaks. This is especially important as governments ease restrictions and allow the public to begin interacting again.
An essential part of this debate is how governments win public trust in order to get the app adoption rates required to make contact tracing apps effective. This is estimated to be over 60% of the public and approximately 80% of smartphone users. One of the first contact tracing apps, TraceTogether launched by the Singapore government in March 2020 has reportedly only been downloaded by less than 20% of the population. While in the UK it’s been reported that the ethics advisory board advising Health Secretary Matt Hancock on the UK CV19 app has warned that too many "false positive alerts could undermine trust in the app and cause undue stress to users".
At Parousya Technologies we have extensive experience in the phone-to-phone Bluetooth Low Energy (BLE) technology used in the TraceTogether app and other similar contact tracing apps such as the Australian COVIDSafe app. We are confident to predict that even with the Google and Apple Exposure Notification API, the phone-to-phone Bluetooth tracing method will suffer more from too many false negatives rather than false positives and therefore will make these contact tracing apps not fit for purpose. We faced the same issue years ago while performing our field trials in the US and have since developed a method to reduce the false negatives.
Our White Paper - Augmentation Strategy - How to Make Pandemic Contact Tracing Apps Fit for Purpose focuses on methods and technologies to overcome user privacy and government mass surveillance issues which impede mass public adoption of contact tracing apps. The paper uses a data acquisition framework to overcome the myriad of technology and environmental problems contact tracing app development teams are only just beginning to appreciate.
We invite feedback and discussion on this whitepaper at Contact Us.