Does it? I'm pretty sure he coined it.

Colbert's joke was based on a comment from a Bush staffer concerning the "reality-based community" (https://en.wikipedia.org/wiki/Reality-based_community):

The aide said that guys like me were 'in what we call the reality-based community,' which he defined as people who 'believe that solutions emerge from your judicious study of discernible reality.' [...] 'That's not the way the world really works anymore,' he continued. 'We're an empire now, and when we act, we create our own reality. And while you're studying that reality—judiciously, as you will—we'll act again, creating other new realities, which you can study too, and that's how things will sort out. We're history's actors...and you, all of you, will be left to just study what we do'.

It's actually a poignant, forward-thinking point about the malleability of "reality" and "facts" under empire, but predictably the third-way neolibs that still dominate the party failed to grasp that and first made a joke out of it, and then out of themselves as it was realized.

The other commenter is correct that Colbert coined the term. It's true that there was a lot of talk in that era about who did or didn't adhere to "reality" and how that related to partisanship, and a segment of the blogosphere that described themselves as the "reality based community," in reponse to that Rove quote, but none of that background context has anything to do with anything when it comes to the fact that the phrase itself, "reality has a liberal bias" is something that came from Colbert.

Of course it was in an intellectual climate where those words were charged with political meaning that made them salient enough to set up the joke. But to say it didn't original with Colbert would be to say that phrase itself was coined by a different person, and if it was, you could say who it was, and when and where. Otherwise it's just a confused detour into the weeds that lost track of the original question of attribution.

This is a huge detour, so to tie it back to the original thread, I think talks of "bias" are poisoned by a false assumption sides are equally estranged from scientific truth. It feels fair to make a both-sides argument, but it really just doesn't hold water under any serious examination especially when it comes to which party affiliation more systematically aligns with, responds to, and believes in scientific consensus.

Being extremely concerned over the precise origin of one particular phrasing of the joke rather than its context and influences is hilariously on-point for the 'reality-based community.' Judicious!

The background context is important, and it's true that Colbert really did coin the term. This really isn't that hard.

It should be possible to hold these two different thoughts in your head at the same time without descending into angry incredulity at anyone offering clarification.

I don't know where you see anger or incredulity in my response. Colbert told the joke first! It also doesn't matter, in exactly the way which liberals misunderstood the comment in the first place! Now it's like a double-joke because it's so ironic, and also the US is probably irrecoverably fucked up. Laughs all around!

An emphatic attempt to say that a correct answer to a simple question either "doesn't matter", or is an obsessive hyperfixation, or is a failure to understand The Real Lesson is a lot of combat to engage in, all for the meager returns of taking a simple yes-or-no question and turning it into an unfocused derail.

Colbert really did coin the term and it really is that simple. You seem to just want to take a question about where a quote came from and turn it into a broader conversation about the history of the 2000s, which is all well and good but.... it's just not an answer to what was being asked.

No.

I thought so too, but any find any evidence of this. Have you got anything?