How the ATO Actually Selects Businesses for Audit

Audit Selection Is Mostly Systematic, Not Random

It's a common worry that an audit might happen for no clear reason — bad luck, or being picked at random. In practice, the large majority of audits are triggered by specific, identifiable risk indicators rather than chance. Understanding how this actually works helps explain why some businesses go years without ATO contact while others, with similar revenue, attract attention.

Industry Benchmarking

The ATO maintains benchmark ranges for typical profit margins, expense ratios and reported income across different industries and business sizes. A business reporting figures well outside the normal range for its industry — unusually low margins, expenses that look disproportionate to revenue, or income that doesn't match the activity visible elsewhere — is more likely to attract a closer look, even if everything is entirely legitimate.

Data Matching Across Multiple Sources

The ATO cross-references tax return data against a wide range of external sources: bank interest and account information, property transaction records, motor vehicle registrations, income reported by platforms and other businesses paying contractors, and data shared by other government agencies. A mismatch between what's reported and what these external sources show is one of the most common audit triggers — and it's largely automated, flagged before a human ever looks at the file.

What This Means in Practice

A Melbourne business with accurate, complete bookkeeping that reflects its real financial activity is unlikely to generate the kind of anomalies that trigger this process. The risk increases with inconsistency — income reported differently across different forms, expenses claimed without matching deductions elsewhere, or figures that simply don't reconcile against what the ATO can already see from other data sources.

Consistency Over Time Matters

A single unusual year is less likely to trigger scrutiny than a pattern of inconsistency across multiple periods. Businesses with a long track record of accurate, on-time lodgement that aligns with reasonable industry expectations build a lower-risk profile over time — one more reason consistent, ongoing bookkeeping matters more than a once-a-year clean-up before tax time.