When it comes to the politics of Obamacare, there’s really only one question that matters: How many Americans are benefiting from the new health care system, and how many are hurting? Problem is, we know more about the first part of the question than the second.

Obamacare’s advocates have pushed hard against Republican attempts to highlight Americans who have been particularly hard hit by the new law. “There’s plenty of horror stories being told,” Senate Majority Leader Harry Reid said in February. “All of them are untrue.”