Opinion polls were a sampling of public opinion within a particular area, as a way to gauge such opinion on various issues. Opinion polls were used in the Federation.
Ru'afo feared that if word of what the Son'a was doing in the Briar Patch reached the Federation, citizens would hold public debates and opinion polls disapproving of the Son'a operation. (Star Trek: Insurrection)
Kathryn Janeway told Arturis in 2374 that there was no time to take a poll to determine what citizens of the Delta Quadrant thought of her temporary alliance with the Borg Collective against Species 8472, made in order to secure passage through Borg space. (VOY: "Hope and Fear")