Quantitative performance measurements produce undesired outputs

Although it has been a trend for the past several decades, quantitatively measuring performance of people or companies may produce unintended consequences.

indiscriminate use and undue confidence and reliance in them result from insufficient knowledge of the full effects and consequences. - [@ridgway1956Dysfunctional Consequences of Performance Measurements]

When measuring performance using single criteria it is likely that people will be incentivized to optimize for those specific performance metrics. This is visible in the publish or perish attitude in academia, for example, which gives raise to problems with citation-based metrics.

Of course it is possible to try to overcome this by quantifying performance using multiple measurements. Of course this will have normalization problems, so it is easy to start building ratios between quantities. The biggest challenge is that this leads to a variety of metrics that change over time and from place to place. This is exactly one of the discussions regarding the exchange rate of scientific output.

The other approach would be to use composite measures of performance, which is essentially a clear way of adding multiple measurements, including their weights. Although it may seem a more appropriate way forward, experience shows that this approach creates strain in organizations, and can induce culture shifts[@ridgway1956Dysfunctional Consequences of Performance Measurements].