Scam artists conned the federal government out of at least $5.2 billion in fraudulent tax refunds last year—and though that estimate is shocking enough—the amount is likely much higher, auditors warned on Monday. Identity tax refund fraud has ballooned in recent years as electronic filing gives thieves an easy way to use stolen social security numbers and simply file phony tax returns. Though the electronic filing has made the tedious process more bearable and user-friendly for taxpayers, it has also made it much easier for criminals to scam the system.