Parallel runs: what auditors actually sample

During pre-migration readiness reviews, clients often ask how many employees to compare between old and new payroll management applications. Volume alone is a weak answer.

Prefer variety over headcount

A sample of thirty carefully chosen employees usually teaches more than two hundred random ones. Include:

• Mid-month joiners and leavers
• Staff with multiple allowances
• Employees near overtime caps
• At least one expatriate or seconded worker if present
• Someone paid across two cost centres

Compare components, not only net pay

Net pay can match while commuting allowance and taxable income diverge. Component-level comparison catches the errors that appear later on withholding certificates.

Document known intentional differences

If the new application uses a cleaner rounding rule you have already approved, write that down before sampling. Otherwise every difference looks like a defect.

Center Wise does not run your parallel payroll. We help you decide where sampling attention should sit so cutover weekend is about confirmed risks, not surprises.