We value the careful handling of client and personal-, passers-by- and/or visitor data. We would like to inform you about the processing of data in the context of our services. Below we will briefly explain per sensor technique if personal data is being processed. More information about privacy can be found in our privacy statement. Further on this page we have included a Q&A with frequently asked questions about wifi counting. If you have further questions, please contact us.  

Couting technique

Infrared beam counters
Sensor data we process do not contain personal data.  

Thermal counters
Sensor data we process do not contain personal data.  

3D Stereoscopic counters
Sensor data we process do not contain personal data.  

Wifi/ Bluetooth counters
Sensor data we process contain, among other, of a pseudonymised MAC-address. The GDPR marks this as personal data.

Object recognition
Sensor data we process do not contain personal data. We do not process video images!


wi-fi counting

In mid-2008, PFM started analysing data from bluetooth and Wi-Fi signals from mobile phones. At the time, PFM was one of the participants in an R&D program subsidized by TNO to develop a market product in this area. 13 years later a lot has changed in technology, algorithms and, above all, regulations.

In the Dutch media there was some coverage about a recent investigation into Wi-Fi counts carried out by the Dutch Data Protection Authority (hereinafter: 'AP').  Although this was specific in the Netherlands, we can imagine more information about Wi-Fi counting could be usefull. Below you will find the most frequently asked questions and answers regarding Wi-Fi counting.

Visitor counts via Wi-Fi, how does that work?

Wi-Fi sensors register all passers-by and / or visitors who have a device with them and have Wi-Fi and / or Bluetooth enabled (the device regularly sends so-called probe requests). The Wi-Fi sensor registers the MAC address, time and signal strength. The MAC address is pseudonymised on the sensor. If the sensor no longer receives a signal for a certain period of time, the status will be adjusted. The data are sent, with a delay, to a central server where the data is further processed. The edits are only done to reach the number of visitors. The data will not be processed and / or analysed in any other way and will not be stored any longer than necessary. Counting via Wi-Fi has the same principle as manually counting people, only the number of passers-by is approximated based on the number of counted devices. 

What can you see based on Wi-Fi counts?

Based on the Wi-Fi signals, PFM determines the number of unique passers-by and the length of stay (within the sensor network). PFM's Wi-Fi sensors do not collect any other data from the mobile devices. 

Are the collected data also used for other purposes than counting passers-by?

No, the collected personal data will only be used for passer-by counting. 

What is a MAC address?

A MAC address, also known as a Wi-Fi address, is a unique code with which a device is recognised. This can be a mobile phone, but also a computer, a printer or an iPad with a wireless network interface. With this MAC address, a device can access a Wi-Fi network. So it is NOT the mobile phone number or an IP address and does not refer to a person, but to a device. However, it is considered indirectly traceable personal data. Without specific knowledge, which also requires access to the data, the pseudonymised code cannot be traced back, cannot be linked and cannot be identified to a unique device. PFM has taken internal and external security measures to prevent this from happening, obtaining more than necessary data and unauthorised persons having access to the data. 

Are Wi-Fi counts now prohibited in the Netherlands?

No. Counting passers-by using Wi-Fi counts is permitted, if it is GDPR compliant. This means, among other things, that: 

  • A legal basis has been determined and that this has been properly recorded.
  • Organisations that use Wi-Fi counts must clearly inform passers-by and / or visitors about this.
  • The retention period is geared to the purpose of the measurement.
  • There is a processor agreement.
  • The personal data are processed privacy-proof in accordance with the processor agreement and the underlying legal provisions.

Is there an opt-out option?

You can always choose to turn off your WiFi. You can also unsubscribe, so that your MAC address is no longer counted and included in research and analysis. You do this by registering the MAC address of your mobile phone in a central opt-out register. Would you like to unsubscribe? Then click here.

Have personal data been stolen (in the past)?


What is the difference between Wi-Fi Tracking and Wi-Fi Counting?

With Wi-Fi tracking, individuals are followed by a device's Wi-Fi signal, contiguous in time and place. A Wi-Fi count is only aimed at counting passers-by at a specific time in a specific place. So, with Wi-Fi counts, passers-by are not followed, but only counted.

Can the Wi-Fi sensors malfunction or interfere with other equipment?

PFM's sensors only pick up the presence of Wi-Fi signals from devices. They do not send signals. Because they do not transmit signals, there can be no disturbances and / or interferences from other devices.

I live in an environment where passers-by are counted through Wi-Fi measurements, what is done with my data?

PFM counts the number of passers-by in and around shops, shopping centers and shopping streets on behalf of others. We use an automatic filter to exclude residents from the counts. PFM knows that signals from residents are mainly measured before and after shop opening times. That is why PFM assumes that when the same signal is seen twice a day, once in the morning and once in the evening, this is a signal from a resident. From that moment on, these signals are automatically filtered out every day. If you live near a sensor, your pseudonymised MAC address will not be included in the data and therefore will not be included in the counts.

Can I see where PFM has installed Wi-Fi sensors?

The sensors are installed at various customers and objects in the Netherlands. We do not release these locations for security reasons. If you want to make sure that your data cannot be used, you can switch off your Wi-Fi or register in our OPT out register. See "Is an OPT out option?"

Can the Wi-Fi sensors pick up the signals from all phones?

Yes, as long as Wi-Fi is enabled on a device, the sensors can pick up the signals. However, “spoofing” is applied to the most current mobile phones from most manufacturers. This means that the phone will broadcast a different MAC address every so often. PFM's sensors can still capture the MAC address, but it cannot be associated with previous MAC addresses of the phone or device in question.