Quantum measurement transitions a system from an uncertain to a certain state, indicating a decrease in entropy for the measured system. However, this decrease does not imply a corresponding increase in entropy elsewhere, as the second law of thermodynamics holds when comparing measured states. The discussion highlights that the entropy of the universe increases during measurement due to the probabilistic nature of quantum outcomes, distinguishing between mutual information and entropy. The von Neumann entropy is a key concept in this context, with its value depending on the purity of the state post-measurement. Ultimately, the relationship between quantum and classical entropy remains complex, with no definitive answer regarding their comparative magnitudes.