Data Minimisation

The test is necessity. For each field on a form, the organisation should be able to say why it is needed and what would break without it. Minimisation applies at three points: what is collected, how much is shared internally, and how long it is kept. It is one of the core principles of the GDPR and appears in similar form in many national laws, including India's DPDP Act. In practice it leads to shorter forms, optional fields marked as such, masking of identifiers in test systems, and scheduled deletion. It works with purpose limitation, which fixes the aim, while minimisation trims the data to fit that aim. Holding less also means less to lose in a breach. Each field dropped is one less item to secure, to retain and to hand over in a legal demand.

A gym's sign-up form asks for date of birth, home address, employer and national ID number. The privacy officer asks what each item is for. The gym needs only name, contact details and an emergency contact, with age confirmed once. The other fields are removed, and old records are cleaned up under the retention schedule.