Selected topics are identified from records based on scoring candidate terms in the records according to a user-specified metric and at least one further metric selected from among frequencies of occurrence of records pertaining to the respective candidate terms, and negativity of sentiment expressed with respect to the candidate terms in the records. A visualization is generated that includes bubbles representing the respective topics, the bubbles including pixels representing corresponding records, where a given one of the bubbles has a shape dependent upon a number of records represented by the given bubble and a time interval represented by the given bubble. Visual indicators are assigned to the pixels in the given bubble according to values of an attribute expressed in the corresponding records for the topic represented by the given bubble.