A relation between an evaluation process and the appraisals is complex, especially in an agile environment (for example article and some other article). So, I will not go any deeper on that subject without knowing what is your "setup".
Surveys show what workers usually want:
- To earn adequately (to market value of their position)
- To have tools and autonomy needed to reach goals
- To progress (and know how to progress)
- To have clear and transparent rules
- To receive regular feedback
- To be under fair and just judgement
So, I believe any rule is fair as long as it is transparent, known upfront, reachable and fairly judged. One can have multiple levels of expertise with progression related to:
- Time / Experience
- Knowledge / Skills
- Achievements
- Relation to other workers (reviewing work, coaching)
- Engagement
Achieving the lower levels of expertise may provide a compensation, also in form of support in trainings, certificates, while higher levels of expertise may require such certificates. Of course, such requirement doesn't mean it's the only criteria of an appraisal...