Formal way to say "from scratch"?

I want to write something along the lines of:

For the purposes of this study, X was developed from scratch.

But the "scratch" here doesn't sound very formal, does it?

Is "from the ground up" any better than "from scratch" in terms of formality? I guess no?

What would be a good way to express this, without sounding too lame? I do want to make it clear that the X really was built, uh, from the ground up.

For what it's worth, the X here is a completely abstract thing. (Think of software, for example.)

"From the ground up", which you mentioned, is actually fine in a professional context, as well, if you don't mind the mental association with buildings and construction.

Perhaps ex nihilo? Given its Romance origin, it ought to be more than suited.