The default position is that money paid to a worker is included, and specific exclusions are then subtracted. Gross wages, salary, commissions, bonuses, holiday and vacation pay, and the straight-time portion of overtime are all normally included — as are employee contributions to retirement and cafeteria plans, because those were wages before the employee deferred them.
Common exclusions include severance, tips reported by the employee, documented reimbursed business expenses, employer contributions to benefit plans, and third-party sick pay. The specifics vary by state.
Businesses that start from take-home pay rather than gross consistently under-report, and the correction arrives at audit with the full policy term behind it.