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Contestability
Also known as: right to contest
The ability of a person affected by an AI-assisted decision to challenge it and have it reconsidered by someone with the authority to change it. It is one of the safeguards UK data protection law now attaches to significant automated decisions.
- redress
- right to contest
- Article 22C
- automated decisions
- appeals
What it requires
Three things: knowing that a decision was made and on what basis, a route to challenge it that is easy to use, and reconsideration by a person who can change the outcome and actually looks at the case. A complaints process that cannot reverse the system's decision, or reviews only whether procedure was followed, is not contestability.
Where the law requires it
Under UK GDPR Article 22C, significant decisions taken without meaningful human involvement must come with the right to make representations, to obtain human intervention and to contest the decision; see automated decision-making. The EU AI Act's Article 86 gives affected people a right to an explanation of certain high-risk decisions, which is what makes a challenge possible.
What good looks like
Tell people how to challenge at the point of decision, give reviewers the case evidence and the authority to overturn, track challenge outcomes as a signal of model error, and feed overturned decisions back into testing. The register entry is inadequate explainability for affected individuals; the control is automated decision-making safeguards.
Sources
Related Terms
Automated Decision-Making
A decision about a person taken by technological means without meaningful human involvement. In UK data protection law, Articles 22A to 22D of the UK GDPR (inserted by the Data (Use and Access) Act 2025 and in force since 5 February 2026) allow significant automated decisions, but only with safeguards: information, the right to make representations, human intervention and the right to contest.
Counterfactual Explanation
An explanation of an automated decision that states the smallest change to the inputs that would have changed the outcome, such as an application that would have been approved with a higher declared income. It tells the affected person what would have made the difference without exposing the model.
Explainability
The ability to give a person an account of why a system produced a particular output, in terms they can act on. Explainability is a property of the account and its audience, not of the model: an opaque model can be explainable, and an interpretable one can fail to be explained.
Human-in-the-Loop (HITL)
A design in which a person reviews, approves or can override what an AI system does before it takes effect. It is only a control if that person has the competence, information, time and authority to disagree, which is why the EU AI Act requires oversight to be designed in and UK data protection law asks whether human involvement is meaningful.