Before revision:  Correcting  their Stage 2 MUE procedure leads to a substantially smaller estimate of \lambda _{z a more subdued downward trending influence of ` other factor' z_{t} on the natural rate.
After revision:  Correcting their Stage 2 model and the implementation of MUE leads to a substantially smaller estimate of \lambda _{z a more subdued downward trending influence of ` other factor' z_{t} on the natural rate.