From the article:
“The “observer effect” is one of the strangest principles of quantum mechanics. The act of observing a quantum particle determines whether it is a wave or a particle. Before an actual observation, it is either or both, but once it is observed, it will be one or the other.
Similarly, obtaining voice-of-customer feedback is not as easy as surveying your customers to ask their opinions, because the act of asking the customer will contaminate your results. Not that surveys don’t produce useful data, but genuine voice-of-customer feedback is subject to its own “observer effect.””