The policy is approved, the consultants leave, and adoption stops.
A familiar pattern: months of careful work produce a good policy framework, competency model or performance redesign. Leadership approves it. Then adoption stalls about when the engagement ends. The gap between policy complete and change complete is where a lot of the value sits, so it is worth planning for.
Manager behavior. If line managers run performance talks the old way, a well-designed framework changes nothing for employees. Training, coaching and early reinforcement for managers usually need as much budget as the design. They often get a fraction.
Systems that match the policy. An HR system still set up for the old cycle, job structure or approval chain undermines the new policy every time someone uses it.
Explaining why. Employees who get a policy without the reasoning treat it as bureaucracy and comply at the minimum.
An owner after the consultants go. A project with an end date and no internal owner for adoption tends to drift back within a year, because nobody's job depends on the new way sticking.
Good HR consulting plans adoption from day one and treats it as a deliverable alongside the policy. The policy is necessary. It was never enough on its own.