
It was sparsely sourced,
but I think the science is VALID.
The Big Bang Theory Season 1, Episode 3

You know, if this experiment is going to
be VALID, I suggest a neutral environment.
The Big Bang Theory Season 10, Episode 4

No, it was a VALID hypothesis.
The Big Bang Theory Season 1, Episode 1

...scientifically VALID protocol
that will make our lives better?
The Big Bang Theory Season 3, Episode 3

He makes a VALID point!
The Big Bang Theory Season 8, Episode 3