Historically, about 1 percent of Form 1040s are audited. Why does a Form 1040 reecting $31,000 AGI

Historically, about 1 percent of Form 1040s are audited. Why does a Form 1040 reflecting $31,000 AGI and a standard deduction have much less than a 1 percent chance while a Form 1040 reflecting $912,800 AGI and $214,790 itemized deductions has a much greater than 1 percent chance of audit?