What is a voluntary response sample? Solution Voluntary response sampling is heavily biased because it focuses on volunteered survey answers rather than a random sampling. What makes this biased is because the only people who volunteer are those who have a particular interest in the topic of the survey. They only include people who choose volunteer, whereas a random sample would need to include people whether or not they choose to volunteer. Often, voluntary response samples oversample people who have strong opinions and undersample people who don\'t care much about the topic of the survey. Thus inferences from a voluntary response sample are not as trustworthy as conclusions based on a random sample of the entire population under consideration..