Abstract: Shared randomness and quantum entanglement are important resources for many information processing tasks, where the former is also called classical correlation. In the classical correlation generation problem, we study the minimum amount of shared randomness or quantum entanglement needed to produce a target classical correlation. Here we review classical protocol, quantum protocol, and classical and quantum hybrid protocols for generating classical correlations. First, in classical protocol and quantum protocol the minimum amount of shared randomness and quantum entanglement required are characterized by nonnegative rank and positive semidefinite rank, respectively. Based on these results, sharing prior quantum entanglement shows exponentially advantage over sharing prior randomness in such a task. Second, since it is hard to access large-scale quantum system in the near future, classical-quantum hybrid protocol is also introduced to produce large scale classical correlations. When the size of manipulable quantum systems is limited, the minimum amount of extra classical resources needed to generate a target classical correlation is characterized by the concept of k -block positive semidefinite rank. In classical-quantum hybrid protocols, it turns out that quantum resources still enjoy huge advantages over classical resources. Therefore, the classical correlation generation problem provides a new insight to compare the computational power of quantum and classical resources.