The raw data behind the story "Early Senate Polls Have Plenty to Tell Us About November" https://fivethirtyeight.com/features/early-senate-polls-have-plenty-to-tell-us-about-november/.
senate_polls
A data frame with 107 rows representing a poll and 4 variables:
Year
Final poll margin
Early presidential approval rating
Early poll margin
See https://github.com/fivethirtyeight/data/tree/master/early-senate-polls