Data Science, Recommender Systems, Collaborative Filtering, Artificial Intelligence, Machine Learning.
(https://goo.gl/y93CsC) Cosine Similarity (https://goo.gl/y93CsC) Both measures are commonly used. The difference is that Pearson Correlation is invariant to adding a constant to all elements. Now, we can predict the users’ opinion on the unrated items with the below equation: Unrated Item