A redacted spreadsheet of an employer's workforce - typically headcount, wage band, age band, dependents, and benefit-enrollment status - used to generate an accurate benefits proposal.
A payroll census is the input EHP uses to return an exact savings proposal rather than a calculator estimate. The census is redacted (no SSNs, no names) and used only for the savings projection. Submitting one is a no-obligation step.
Definitions only do so much. A live walkthrough of how all of this connects in your business takes about half an hour.