I never finish a vocal jazz score without including chord changes in the vocal part.
There was a time when I didn’t, because singers don’t sing changes. Haha. But there are at least three good reasons to include chords in scores just for singers.
- Conductors without rehearsal pianists can play chords or roots when they’re not playing vocal parts.
- Conductors can use the chord changes to speed analyze the vocal parts, to make sure notation is correct, and to help singer balance effectively.
- They are an educational aid to students; if they’re on the page, they’re more likely to look at them during down moments.
- Learning to improvise with the changes in front of you is important.
I always make sure the changes are in my scores, and one of the first things I do in score that don’t have changes is copy the changes in from the piano part, or analyze the notated piano part.