How to define a "representative sample" for community engagement?

My office is hosting several community engagement events in partnership with other agencies in the late summer and fall, and we’re working on how to evaluate whether we’ve meaningfully represented different subgroups in the community we’re working with in these events.

Most of our thinking so far has centered on somewhat standard measures of demographic distribution, geographic distribution, and certain life experiences that are relevant to our event question, but this feels limited. This event is also not typical of our office’s events because all participants will be enrolled in one of four assistance programs run through our partner agencies. Any examples on how others have evaluated this before, especially in a local government context, are helpful!