transform feedback input and output size

I have a small question about transform feedbacks in OpenGL.

Is it possible for my output to be a different size than my output ? Let say a VS like:

in vec3 pos;
in vec3 move;

out vec3 newPos;

void main()
{
  newPos = pos + move;
}

So my output buffer would just be the new position!

Or the other way around, have more outputs than inputs.