Where co-determination applies to an evaluation method, agreement is a condition of use, not a courtesy.
Why it matters when the plan changes
A programme can be approved by the board, funded and contracted, and still be unable to start, because in some jurisdictions the works council, a body distinct from trade unions and operating at site or firm level, holds an agreement right over exactly the kind of instrument being introduced. Discovering that at rollout is a negotiation from a weak position. Discovering it at design is a conversation about terms, including what a data protection agreement will actually permit.
The tension is that co-determination slows things and improves them. A council that has agreed the purpose, the access model and the retention of an assessment has removed the single largest source of later resistance, since the GDPR itself leaves member states room to set such terms through collective agreement. The cost is time at the start; the return is a programme that does not stall in month four.
In practice
A group signs a framework agreement for leadership assessment across its European entities. In its German subsidiary the works council has an agreement right over the questionnaire. Nobody consulted it. The subsidiary's rollout waits a quarter while terms are negotiated that a design-phase conversation would have settled in a fortnight, and the tone of that negotiation is set by the fact that the contract was signed first.
Evidence
Works councils are employee bodies at site or firm level, distinct from unions, whose powers differ by country.
Works council, Wikipedia (2026)Member states may set more specific national rules for processing employee data, including through collective agreements.
Article 88, General Data Protection Regulation (2016)
What it cannot tell you
Co-determination establishes that agreement is required; it does not specify what that agreement should contain, how long negotiation will take, or which of its forms, board-level representation, works council agreement, applies in a given country. It is silent on enforcement where a jurisdiction lacks a works council, and on multinational structures where rights differ subsidiary by subsidiary.
Questions
Germany, Austria and the Netherlands are the usual examples, with agreement rights over specific workplace measures. The Nordic countries rely more on collective agreements and consultation. The detail differs enough that a multi-country rollout has to be checked jurisdiction by jurisdiction rather than assumed from the strongest or weakest case.
Working time, monitoring, personnel questionnaires, evaluation principles and selection guidelines are common subjects of agreement rights. Article 88 of the General Data Protection Regulation (2016) itself allows member states to set more specific rules for employee data through collective agreement, which is why an assessment instrument needs the council's agreement first.
No. Consultation means the employer must inform and hear representatives before deciding. Co-determination means the employer cannot decide without their agreement, or without a conciliation body settling the matter; as Wikipedia's entry on the works council (2026) notes, such bodies are distinct from trade unions and operate at firm level. Treating one as the other is a common mistake.
In the design phase, before contracts are signed. Involving representatives early means purpose, access and retention can still be shaped. Involving them after signature means either proceeding and being refused, or renegotiating commitments already made, with the relationship damaged either way.
What is collected, why, who sees individual results, whether the results can affect a person's standing, how long data is kept and who decides. Those are answerable, and the answers that cause trouble are the ones that describe a future capability as though it were current.