Sales people get incentives based on sales, and NFL running backs get incentives based on yards gained. One of the difficulties with incentives is to be sure that they encourage the right behavior.
What do incentives get respondents to do? Usually, simply to show up. It’s the moderator’s job to draw them out. This humorous video from SNL takes a look at what can happen if respondent incentives are mis-applied. If you are a qualitative researcher, be sure and close the door to your office. You will recognize these respondents and you will laugh out loud.