The author of the article asks "Does it make sense from either an equity or revenue standpoint to focus IRS’s limited firepower on the poorest taxpayers among u

The author of the article asks "Does it make sense from either an equity or revenue standpoint to focus IRS’s limited firepower on the poorest taxpayers among us?" But he has only established that the IRS sends more of these letters to the (self-reported) poorest taxpayers, and not that they actually spend more of their limited firepower on them.