Metrology supplies valid information about the production. Utilized in control loops metrology often is the enabler to a capable production. Benefits in terms of a contribution to the production’s value added is generally unknown. This paper answers the question how the use of or investments in metrology can be rationally justified - not only on the basis of a cost minimization, but as an assessment of production performance due to measurements. A decision-theoretical model comparing the deployment of metrology with compared to an abdication of measurements enables the necessary quantification of the benefits. Embedding the decision model in quality control loop shows that the feedback of measurement information leads to a considerable process improvement.