Ch 14.6.5–14.6.6 - Legitimacy & proportionality
Legitimacy and proportionality of monitoring
Monitoring needs a lawful basis - usually the legitimate-interests balancing test, not consent, whose use the WP29 said is very limited for monitoring. Monitoring must also be proportionate: wholesale reading of all employee emails to catch leaks is disproportionate, but automated, technical-security email monitoring is likely proportionate. Proportionality links to data minimisation - prefer traffic data (who/when) over content. are useful proportionality markers.
| Activity | Likely assessment |
|---|---|
| Wholesale monitoring of all employee emails to detect leaked confidential info | Disproportionate |
| Wholesale automated monitoring to ensure IT security via technical weakness-detection | Likely proportionate |
| Monitoring email traffic data (who sent, when, size, number) | Preferred / proportionate |
| Actually opening emails to read the contents | Usually disproportionate |
| Screening emails to detect viruses and filter spam | Justified as appropriate security |
- The WP29 said the use of consent to legitimise email monitoring is very limited - and the same applies to all types of monitoring.
- Monitoring involving sensitive data is problematic; Article 9 (e.g. via law or a collective agreement) may be needed, and some countries allow it for diversity, equality and inclusion purposes.
- Consider collective agreements and consult works councils - in Germany required for firms with as few as five employees; in Austria a monitoring system interfering with human dignity needs a works-council agreement first.
- Prevention is more important than detection (WP29) - e.g. blocking certain websites rather than recording what employees view.
- Consider human rights law: CJEU on the Charter and ECtHR on the ECHR.
Consent rarely legitimises monitoring
For monitoring, consent is very limited - rely on the legitimate-interests balancing test instead, and keep collection proportionate (traffic data over content).
Key terms - quick answers
What is “Legitimate-interests balancing test”?
Weighing the employer's legitimate interest (e.g. protecting against threats) against employees' rights; the usual basis for monitoring.
What is “Data minimisation”?
Personal data must be adequate, relevant and limited to what is necessary for the purpose; supports preferring traffic data over content.
What is “Traffic data”?
Metadata about communications (sender, time, size, number) - less intrusive than opening message content.
What is “Collective agreement”?
An agreement that, if it acknowledges certain monitoring, suggests the proportionality balance has been struck.
Sources and study method
This independent lesson uses active recall, spaced retrieval and scenario practice. Read the full study method.