How should an employer assess an internal candidate for a role when they have not performed at that level before?

It is often difficult to assess an internal candidate for a role because they may not have performed at that level before. During the interview, the employer could explore whether or not the candidate has had similar experiences to those that they would experience in the target role. It could also explore the candidate's past experience learning new skills and responding to new situations. The employer could use alternative assessment methods to test the candidate's capability, for example a simulation-based assessment that puts the candidate in situations that they are likely to experience in the new role. The employer should also consider what support would be available to help the employee to develop into the new role, for example training.