According to this taxprotoday article,the IRS audits are just .5% of tax returns and there are 12 “red flags” to look after:
- Misreporting or not reporting income
- Earning more than $200k
- Big changes in income
- Unusually high charitable deductions
- Unusually low salaries
- The wrong social security number
- Hobby losses
- Inconsistent Alimony reporting
- Home Office expense
- Overly rounded numbers
- Big Meals and Entertainment expenses
- Owning a cash business
For now, this page is simply a peg-holder, I will come back and write my opinion about each of these, but for now, check out their article:
https://www.taxprotoday.com/list/12-red-flags-that-can-trigger-an-irs-audit