Polls that measure changes in public opinion over the course of days, weeks, or months by repeatedly asking respondents the same questions and measuring changes in their responses are called:

Tracking Polls

Explanation:

The tracking polls which are often referred to as the opinion polls, are known as or described as the human study or research survey of the audience opinion from the specific population size. Tracking polls are mostly formulated in order to represent belief of a sample size thereby administrating the series or set of questions and then thus deducing the vague notions.