The data displayed in these graphs come from daily or weekly tracking surveys conducted by YouGov.
For each survey, a representative sample of 1,500 respondents is selected from YouGov’s U.S. research panel. Panelists are invited to each survey, based upon their age, gender, race, and education, in proportion to their frequency to the frequency of adult citizens in the most recent American Community Survey.
Responding panelists are then weighted according to their demographics, voter registration status, and 2016 Presidential vote. The margin of error for adults in each survey is approximately 4% and for registered voters is approximately 5%. Trend lines are computed using a LOESS smoother (Cleveland and Devlin, Journal of the American Statistical Association, 1988) to reduce random fluctuations in the data due to sampling variability.