Do we need job evaluation expertise to use it?

There are levels to it.

Scoring an individual role is relatively straightforward. If you know the job, the five plainly defined factors walk you through the grading process, and the engine does the calculating. No JE background needed and teams are typically scoring confidently within weeks of training.
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Building a consistent structure itself, the grade boundaries, the anchor roles, and hierarchy that every score lands in, takes more skill and experience. And it's the part that determines whether the whole thing holds up later.
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Once that structure is in place, the expertise is effectively built in. Your team scores new roles, handles restructures and keeps everything current without needing a reward specialist on staff or a consultant on call.