With the Iowa caucuses scheduled for Monday night, the final Des Moines Register poll — traditionally seen as the gold standard survey of the caucus electorate — was pulled from publication after questions about its methodology.

On Saturday night, the newspaper said former South Bend, Ind., Mayor Pete Buttigieg may have been left off the list presented to a caucus-goer in at least one call.

Most surveys show a jumble at the top for former Vice President Joe Biden, Sen. Elizabeth Warren, Sen. Bernie Sanders and Buttigieg. But many were looking to the Register poll to see if that was changing.