Contrary to popular misconception, the Observer Effect and the Uncertainty Principle are not actually the same thing. The Observer Effect is something that can happen in all sorts of experiments, classical or not, and is a result poor experimental design. The Uncertainty Principle is a quantum mechanical phenomenon that cannot be controlled for, because the uncertainty of a particle's position and momentum is an inherent property of the matter wave nature of quantum objects.

Part of this stems from early use of the words "observer" and "measurement" when describing the Uncertainty Principle. Most interpretations of quantum mechanics provide specific definitions of these words which differ from their use in common language. The Many Worlds Interpretation, for instance, has no Observer, and defines a measurement as any thermodynamicly non-reverseable process.