This post is not for the RW'ers, who are too stupid to understand it and/or too biased to accept it, but, forthe rest of you,
the UPI poll is based on self-selection:
Self-selection bias
From Wikipedia, the free encyclopedia
In
statistics,
self-selection bias arises in any situation in which individuals select themselves into a
group, causing a
biased sample with
nonprobability sampling. It is commonly used to describe situations where the characteristics of the people which cause them to select themselves in the group create abnormal or undesirable conditions in the group. It is closely related to the
Non-response bias, describing when the group of people responding has different responses than the group of people not responding.
Self-selection bias is a major problem in research in
sociology,
psychology,
economics and many other
social sciences.
[1] In such fields, a poll suffering from such bias is termed a
self-selected listener opinion poll or "SLOP".
[2]