UK, Information Commissioner's Office, Tools for completing a data protection impact assessment (DPIA) > Sample Data protection impact assessment: Online retail > Step 4: Assess necessity and proportionality ([Internet, 2023-09-21](https://ico.org.uk/for-organisations/uk-gdpr-guidance-and-resources/childrens-information/childrens-code-guidance-and-resources/dpia-tools/online-retail/step-4-assess-necessity-and-proportionality/))