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 ...

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.

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.