More importantly, entering the South Carolina primary, the pledged delegate count was 52-51. CNN’s poll two weeks out projected an 18 point Clinton win. Ann Selzer, the best pollster in the United States, projected a 22 point Clinton win. RealClearPolitics’ polling average projected a 27.5% win. FiveThirtyEight was much bolder in projecting a 38.3% Clinton win. The early full exit poll said Clinton had won by 36%, pretty close to FiveThirtyEight’s call. Tellingly, white people in that exit poll went for Sanders 58-42. But the final results said Clinton won by 47.5%, an 11.5% exit polling miss. And the exit polls had to adjust their initial figures to a 53-47 Clinton win with white Democrats in South Carolina.
Three days after South Carolina’s primary, Clinton seriously outperformed her exit polling projections again in a bunch of states on Super Tuesday, including Massachusetts where she went from a projected 6.6% loss to a 1.4% win. Super Tuesday set the narrative that Sanders had no chance of beating Clinton in pledged delegates.
Correlating Exit Polling Misses and Bad Machines
Let’s be clear: yes, correlation does not equal causality.