Corona App: What’s the Difference Between Tracking and Tracing?

In discussions about a Corona app, the terms are often used synonymously, although they mean different things. We explain the differences and how the app is supposed to work in Germany.

Corona app

Björn GreifEditor

For days, politicians, privacy and security experts in Germany have been discussing heatedly and controversially about a Corona app for keeping infections at bay. In addition to objective arguments, many rumors, fake news, and conspiracy theories are circulating on the subject. They often use the terms ‘tracking’ and ‘tracing’ synonymously, although they have different meanings.

To provide more clarity, we will explain the difference between tracking and tracing as well as the basic functionality of the Corona app planned in Germany.

Tracking or Tracing?

In logistics, tracking generally means following the path or current location of a delivery in real time. (Where is the delivery located right now?) Tracing, on the other hand, means following the path of a delivery backwards from its current point to where it started. (Where was the delivery in the past, which route did it take, which stations did it pass through?)

Regarding the Corona app, the terms must be distinguished similarly.


Tracking is about gaining insights in real time. A tracking app can, for example, determine a person’s current location using geodata (e.g. via GPS coordinates or radio cell location). If it additionally tracks who has been where and when, it even allows to create detailed movement profiles. However, this is not the purpose of the planned Corona app.


Tracing is all about gaining insights in retrospect. A tracing app can be used, for example, to trace physical contacts between people. Using Bluetooth, a technology that enables digital devices to communicate with each other over short distances, it can measure the distance between smartphones on the basis of the strength of the radio signals and thus detect encounters between users (proximity tracing).

The Corona app planned in Germany is intended to enable the tracing of potential corona contacts and inform users if they have had epidemiological relevant contact with a corona infected person. It is therefore not a tracking app, but a tracing app.

How the Corona App Will Work

The download of the Corona app will be voluntary for users in Germany. Once they turn on Bluetooth on their phone, the app will continuously search in the background for other devices on which it is installed.

If person A now comes into the immediate proximity (defined as less than two meters away) of person B for a certain period of time (planned to be at least 15 minutes), the app stores this encounter in the form of an anonymous temporary ID on the user’s phone. The encounter data does not contain any personal information about the app users or where they met. Therefore, it’s not possible to create movement profiles or identify persons by name.

If person B is later tested positive for Covid-19, she will indicate this in the app. The app then anonymously informs person A and all other people who have had close contact with person B that they may have been infected. Those who have been informed in this way should then contact their local health authority and get tested if possible. In case they are infected, they can also warn all relevant contacts via the app.

In general, the more people use the Corona app, the better the chances are that it will help to contain the spread of the new coronavirus.