[en] We consider a simple model in which a small fraction of runaway electrons produce the often-observed x-ray emission in pinches. We show the turbulent collision frequency scales as v-3, from fairly general arguments. Simple scalings result, linking the number of runaways with their energy. Fitting to a recent experiment gives a pinch field exceeding the applied field by approx.400. Future experiments can check the scaling without knowing the pinch electric field