Sampling error, however, is oversimplified when presented as a single number in reports that may include subgroups, poll-to-poll changes, lopsided margins and results measured on the difference ...

Some of the better-known statistical rules of thumb that a smart consumer might think apply in polls are more nuanced than they seem. In other words, as is so often the case in life, it’s complicated.

The potential degree of this error in a particular poll is reflected in the margin of sampling error, a measurement of how closely the poll reflects the full population.