Jerry Muller legt in zijn boek The Tyranny of metrics waarom het sturen op cijfers niet zonder risico's is:
Campbell's Law and Goodhart's Law are warning about the inevitable attempts to game the metric when much is at stake. Gaming the metrics takes a variety of forms.
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Gaming through creaming: practioners find simpler targets or prefer clients with less challenging circumstances, making it easier to reach the metric goal, but excluding cases where succes is more difficult to achieve.
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Improving numbers by lowering standards: one way of improving metric scores is by lowering the criteria for scoring. Thus, for example, graduation rates of high schools and colleges can be increased by lowering the standards for passing. Or airlines improve their on-time performance by increasing the scheduled flying time of their flights.
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Improving numbers through omission or distortion of data: this strategy involves leaving out inconvenient instances, or classifying cases in a way that makes them disappear from the metrics. Police forces can "reduce" crime rates by booking felonies as misdemeanors, or by deciding not to book reported crimes at all.
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Cheating: one step beyond gaming the metrics is cheating - a phenomenon whose frequency tends to increase directly with the stakes of the metric in question.