Officials involved with the trial say the combination therapy is still a valid concept that deserves further study.

But I do know that the concept of training is a very valid concept.

Is cosmopolitan even a valid concept in this day an age anyway?

"Comparable worth" is a valid concept best advanced in the context of collective bargaining.

Some people accept provocation as a valid legal concept, but express serious concerns about the context in which it is used.

He communicates a valid concept and sees that the listener doesn't miss a note.

Despite these subtleties, causality remains an important and valid concept in physical theories.

That's certainly what his first followers thought, and it was a useful and valid concept for two thousand years.

Many clinicians believe that andropause is not a valid concept.

"Free will isn't a valid concept when you're involved."