If a margin of error is plus or minus 3 percentage points, the margin of error on the difference between them is about double – or 6 percentage points, in this example.

For example, a sample of 600 voters will have a larger margin of error – about 4 percentage points – than a sample of 1,000 voters, which has a margin of error of just over 3 percentage points.

As Americans await election results, many are looking to the polls for clues. From the margins of error to methodology, here’s what to know about presidential polls.

The margin of sampling error for all voters is estimated to be plus or minus 0.4 percentage points. Potential sampling error is greater in the estimates for smaller subgroups.

As Americans await election results, many are looking to the polls for clues. From the margins of error to methodology, here’s what to know about presidential polls.