What do we really measure and what relevance has the data to us personally? Are measurements and their interpretations biased by our subjective views?

In a world that is increasingly subdued to digital quantification, the human becomes more and more the focal point of measurements. The question arises as to whether the interpretation of such readings should be left to experts or whether each of us should become an expert. Should we know what is really measured and how to interpret the numbers? Is understanding such measurements an advantage or are we simply deluged with numbers?