In Reply to: The margin of error in a poll average is smaller than the posted by mh on April 24, 2026 at 10:31:55
Margin of error for individual polls is typically around 4–5%. Even when you aggregate multiple polls, the uncertainty doesn’t disappear—it just shrinks more slowly. For example, combining 20 polls might still leave you with roughly a 2% margin of error, because the margin of error shrinks by the square root of the sample size.
That’s why most high-quality electoral polls cap out at around 1,000–1,300 respondents: beyond that, the gains in precision are minimal. Even with extremely large samples—30,000 or more—you’re still looking at about a 1% margin of error.
As for Trump’s polling trend, most of the decline happened earlier in the year. Recently, his numbers have been relatively stable, contrary to the impression you’re suggesting.