In this age of dataharvest many feel a sense of empowerment in their ability to measure and extrapolate from measurement. And indeed, measurement is a magnificently useful tool. But if held too tightly, if the seeming certainty it provides becomes a motivation in itself, the process of measurement can turn on its user.
One common way the tool is misused is when it is transformed in the mind of a naive thinker into a crystal ball, a viewport into some strange place called reality, and anything not included is assumed to be non-existent. The gradual hypnotic influence of measurement is captured in what some have called the McNamara fallacy:
The first step is to measure whatever can be easily measured. This is OK as far as it goes. The second step is to disregard that which can’t be easily measured or to give it an arbitrary quantitative value. This is artificial and misleading. The third step is to presume that what can’t be measured easily really isn’t important. This is blindness. The fourth step is to say that what can’t be easily measured really doesn’t exist. This is suicide. (Wikipedia)