Alex Moskalyuk reviews Yes! 50 Scientifically Proven Ways to Be Persuasive and offers up this summary of #15:
Labeling people into a social group tends to increase their participation ratio. A group of people was interviewed regarding their voting patterns. Half of them were told that based on their response criteria, they were very likely to vote, since they were deemed to be more politically active. Later on the election day that specific half did indeed turn up a participation rate that was 15% higher than participation of the control group.
Hmmm. This sounds pretty handy as sort of the mirror image of a push poll. (1) Identify people likely to vote for your guy, (2) call them up and ask them to participate in a survey because they're "politically active," (3) watch them show up to the polls at a higher rate than normal. Result: as long as you've done (1) reasonably well, instant boost for your candidate. Campaign managers take note.