A system and method for measuring engagement effectiveness with respect to a service agent by analyzing a conversation between the agent and a customer in a social media environment. A conversation history between the agent and the customer can be mapped into a multi-resolution space based on different time frames via a mapping module. A polarized topical and sentimental distance between the continuous conversations can be calculated by applying a topic-sentiment mixture model and a divergence theorem onto the conversation history with respect to the time frame. Finally, the polarized topical distances can be aggregated in a time-sensitive way based on a time function and an effectiveness score can be calculated and represented as a weighted pyramid kernel of multiple levels. Such a time-sensitive pyramid kernel function based on the implicit topical and sentimental correspondences between daily conversations enables discriminative evaluation for the agent engagement in a customer care.