The Harris Online Poll uses probability sampling and statistical methods to weight responses and uses recruitment to attempt to create a panel (sampling frame) that is as representative as possible. But the panel also consists of volunteers and suffers, to some extent, from voluntary response. In addition, panel members are Internet users, and it is not clear that such a panel can be representative of a larger population that includes those who do not use the Internet.
As Crouper points out in his The Public Opinion Quarterly paper, “it is not the fact that a very large panel of volunteers is being used to collect systematic information on a variety of topics that is of concern, but the fact that the proponents of this approach are making claims that these panels are equal to or better than other forms of survey data collection based on probability sampling methods (especially RDD [random digit dialing] surveys). The claim goes beyond saying that these panels are representative of the Internet population to claiming that they are representative of the general population of the United States. These assertions rest on the efficacy of weighting methods to correct deficiencies in sampling frames constituted by volunteers. We need thorough, open, empirical evaluation of these methods to establish their validity.”
Thus, the verdict is out on whether the Harris Poll Online provides accurate information about well-