The very first post at FactCheck.org referenced that great line from the late Sen. Daniel Patrick Moynihan: “Everyone is entitled to their own opinion — but not their own facts.”

During the years I spent at FactCheck, I certainly wittnessed my share of politicians trying to make up their own facts. And while I wasn’t allowed to say this at the time, it was always pretty clear (to me, anyway), that one side was making up a lot more facts than the other. Republicans have happily embraced half-truths and outright falsehoods. From “Death Panels” to climate change denialism to the austerity discussion to Paul Ryan’s budget math, the GOP appears to have embraced a policy of Making Stuff Up.

But now it seems that conservatives’ War on Facts has entered a new phase. If the facts are against you, just stop collecting them.

Rep. Jeff Duncan, a South Carolina Republican, has introduced a bill that would prevent the federal government from collecting data about the economy.

That’s right. The bill would require that the Census Bureau stop collecting the information that economists use to calculate (among other things) the unemployment rate, the labor force participation rate, housing construction rates, trade deficits, and much more.

So you might well be saying, “This sounds like a pain for economists, but why should I care if a bunch of stuffy economists are inconvenienced?”

The answer is that without this information, it will be impossible to tell how much any legislation coming out of the Congress costs.

When the Congressional Budget Office calculates the cost of a particular piece of legislation, they have to have something to compare it against. They do this by calculating a budget baseline–that is, they look at how much the federal government will spend and how much revenue it will collect under current law. It’s that last part that’s important here.

To know how much money the government will collect in taxes, you have to know a lot of things about the economy generally. Much of this is incredibly complicated, and a whole lot of extremely smart CBOers spend hundreds of person-hours each year trying to produce an economic forecast. Not being an economist, I can’t tell you exactly what goes into all of those models, but I do know one thing for sure.

If you want to know how much tax revenue you’ll collect, you pretty much have to know how many people have jobs.

But, then, if you’re just planning to make up your own numbers anyway, you probably don’t much care whether the CBO has the data it needs to produce accurate estimates.