Working code is king, but in the IRS's case it's a very expensive king. A huge amount of fraud happens by exploiting a timing attack against the batch processi

Working code is king, but in the IRS's case it's a very expensive king. A huge amount of fraud happens by exploiting a timing attack against the batch processing architecture of the existing process. The system only has visibility into data from previous batches, it's blind to what's been done during the the currently processing batch. One exploitable artifact of this is that if you try to claim someone as a dependent (and potentially get child tax credits, EIC, etc) and they've already been claimed in a previous batch, your return will get rightfully rejected. But if multiple returns claim that person in the same batch, and they haven't been claimed in a previous batch, they'll all get accepted. The IRS will catch it after the fact, but by that point they've already paid out the fraudulent returns. If it's something like a misunderstanding between spouses on who claims a kid, it's likely they'll straighten it out and get their money back. If it's outright fraud, then they'll probably be out that money completely (plus investigative costs). That's just one example, but there are billions of dollars worth of fraud that happens every year which could be prevented by migrating the IRS systems from offline batch processing to an online/real-time transactional architecture.